Lake Forest City Council
March 17, 2026

January 2026

EXECUTIVE SUMMARY
This Noise Impact Study (Study) evaluates the potential noise, and vibration impacts from the construction and operation of the proposed Costco Wholesale Warehouse (Costco; Project), located at 26602 Towne Centre Drive in the City of Lake Forest, California (Project Site). The purpose of this Study is to determine whether the proposed Project would generate any significant impact pursuant to CEQA requirements.

Findings
To analyze the potential noise impacts of Project construction and operations, the existing ambient noise environment at the six selected sensitive noise receptors (identified as R1 through R6) in the vicinity of the Project Site were measured and tabulated in this Study. The measured ambient sound data were utilized as baseline noise levels, and in conjunction with the applicable standards and guidelines, was used to define the Project noise impact thresholds.

All technical terms and levels of significance are explained in the body of this Study.

The key findings of the Study, as more fully described later in this Study, are as follows:

Construction Noise Impacts
 The estimated noise level from Project on-site temporary construction activities would temporarily increase current ambient noise levels in the vicinity of the Project Site.

However, noise levels associated with Project construction would be below the maximum 80 dBA (Leq) Project significance threshold.
 The estimated noise level from Project off-site construction trucks would also be below the 80 dBA (Leq) Project significance threshold.
 Therefore, noise impacts associated with Project construction would be less than significant.

Construction Vibration Impacts
 The estimated vibration levels from Project on-site temporary construction activities would be below the significance threshold for building damage at the nearest off-site buildings to the north, south, east and west of the Project Site.  The estimated vibration levels from the Project’s on-site temporary construction activities would be below significance threshold pursuant to human annoyance criteria at nearest off-site vibration sensitive receptors surrounding the Project Site.

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 Therefore, vibration impacts pursuant to both building damage and human annoyance associated with Project construction activities would be less than significant.

Operational Noise Impacts
 Noise levels associated with the Project operation, including on-site mechanical equipment, loading dock operation, warehouse delivery trucks, trash compactors, parking lot operation, and the tire installation center would be below the Project significance thresholds (City’s exterior noise standards).  A composite operational noise analysis was performed to evaluate the noise impacts from all Project-related on-site noise sources (concurrent operation), including mechanical equipment, loading dock operation, warehouse delivery trucks, trash compactors, parking lot operation, and the tire installation center. The estimated daytime composite noise levels due to the Project would range from 38.7 dBA (Leq) at receptor R1 to 48.7 dBA (Leq) at receptor R6, which would be below the Project daytime significance threshold of 60.0 dBA (Leq) at receptor R1 and 65.0 dBA (Leq) at receptor R6. The estimated nighttime composite noise levels due to the Project would range from 36.6 dBA (Leq) at receptor R1 to 46.5 dBA (Leq) at receptor R6, which would be below the Project nighttime significance threshold of 50.0 dBA (Leq) at receptor R1 and 65 dBA (Leq) at receptor R6. Therefore, the composite noise level impacts due to Project operation would be less than significant; and, therefore, no mitigation measure is required.
 A noise analysis was conducted to evaluate the potential for sleep disturbance, associated with the warehouse delivery trucks. Potential sleep disturbance was analyzed using the Sound Exposure Level (SEL) metric following the recommended SEL noise limit from the LAX South Airfield Improvement Project EIR. The estimated SEL due to a delivery truck would range from 56.7 dBA SEL at the exterior of receptor R2 (nearest residences to the northeast) to 73.8 dBA SEL at the exterior of receptor R4 (nearest residence to the southeast). As analyzed, the estimated SEL levels at the off-site sensitive receptors would be well below the 94 dBA SEL exterior noise limits. In addition, the estimated SEL at the interior of the nearest residences, with the window opens (worst-case noise scenario) would be approximately 43.7 (residences to the northeast) to 60.8 dBA SEL (residences to the southeast), which would be below the 81 dBA SEL interior noise limits.
 The Project off-site traffic would result in a maximum noise increase of 2.5 dBA CNEL along Towne Centre Drive (between Alton Parkway and Bake Parkway). The estimated traffic noise levels along Alton Parkway (East of Portola Parkway), Rancho Parkway, Town Center Drive (between Alton Parkway and Bake Parkway), and Portola Parkway (North of Alton Parkway) fall between 60 dBA and 65 dBA CNEL, Item: 11
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which would be below the 3 dBA CNEL significance threshold (applicable to noise levels between 60 dBA and 65 dBA CNEL). The noise increase at all other roadway segments is less than 1.2 dBA CNEL, which would be below the 1.5 dBA CNEL significance threshold (applicable to noise levels greater than 65 dBA CNEL).

Therefore, noise impacts associated with Project off-site traffic would be less than significant.
 The cumulative traffic (including existing plus future growth, related projects and the Project) would result in a maximum noise increase of 2.8 dBA CNEL along Towne Centre Drive (between Alton Parkway and Bake Parkway). The estimated traffic noise levels along Alton Parkway (East of Portola Parkway), Rancho Parkway, Town Center Drive (between Alton Parkway and Bake Parkway), and Portola Parkway (North of Alton Parkway) fall between 60 dBA and 65 dBA CNEL, which would be below the 3 dBA CNEL significance threshold. The noise increase at all other roadway segments

1.4 dBA CNEL or lower, which would be below the 1.5 dBA CNEL significance threshold. Therefore, noise impacts associated with cumulative off-site traffic would be less than significant.

Conclusions
In summary, the noise and vibration impacts associated with the construction and operation of the Project would be less than significant.

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1 INTRODUCTION
This Noise Impact Study (Study) evaluates the potential noise and vibration impacts from the construction and operation of the proposed Costco Wholesale Warehouse, located at 26602 Towne Centre Drive in the City of Lake Forest, California (Project Site/Project), as shown in Figure 1 (on page 6).

1.1 Project Description
The Project includes a new 165,068 square-feet Costco warehouse and various site circulation, surface parking, and landscaping improvements. The proposed warehouse would be open to Costco members with operating hours from 10:00 a.m. to 8:30 p.m. Monday through Friday, from 9:30 a.m. to 6:00 p.m. on Saturday, and from 10:00 a.m. to 6:00 p.m. on Sunday. In addition, the warehouse would be open to Costco Executive members only starting from 9:00 a.m. daily. The warehouse is expected to receive up to 16 deliveries per day, between 2:00 a.m. and 10:00 a.m., with maximum of two deliveries per hour.

The objectives of this Study are to:
a) Evaluate the Project’s construction-related noise and vibration impacts on sensitive uses in the vicinity of the Project Site,
b) Determine potential noise impacts on existing off-site noise sensitive uses from Project operation-related noise sources, on-site stationary and off-site mobile noise sources, and c) Provide noise mitigation measures to avoid or reduce the potential noise impacts, if required.

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2 ENVIRONMENTAL SETTING

2.1 Fundamentals of Sound and Environmental Noise
Noise is commonly defined as sound that is undesirable because it can interfere with speech communication and hearing, may cause sleep disturbance, or may otherwise be considered annoying (unwanted sound). The decibel (dB) is a conventional unit for measuring the amplitude of sound because it accounts for the large variations in sound pressure amplitude and reflects the way people perceive changes in sound amplitude.1 The human hearing system is
not equally sensitive to sound at all frequencies. Therefore, to approximate this human frequency-dependent response, the A-weighted filtering system is used to adjust measured sound levels (dBA). The term “A-weighted” refers to filtering the noise signal in a manner that corresponds to the way the human ear perceives sound. Examples of various sound sources and decibel levels in outdoor and indoor environments are provided in Table 1 (on page 7).

Generally, people judge the relative magnitude of sound sensation by subjective terms such as “loudness” or “noisiness.” To the normal human ear, a change in sound level of 3 dB is considered “just perceptible,” a change in sound level of 5 dB is considered “clearly noticeable,” and a change (i.e., increase) of 10 dB is generally recognized as “twice as loud.”2

2.1.1 Outdoor Sound Propagation
In an outdoor environment, sound levels attenuate (reduce) through the air as a function of distance. Such attenuation is commonly referred to as “distance loss” or “geometric spreading,” and is based on the noise source configuration (e.g., point source, or line source). For a point source, such as a fan, the rate of sound dissipation is about 6 dB per doubling of distance from the noise source. For example, a fan generates a sound level of 66 dBA at a distance of three feet would attenuate to 60 dBA at a distance of six feet. For a line source, such as a constant flow of auto traffic on a roadway, the rate of sound attenuation is about 3 dB per doubling of distance.3

In addition, structures (e.g., buildings, parapet walls) and natural topography (e.g., hills) that obstruct the acoustic line-of-sight between a noise source and a receptor further reduce the noise level if the receptor is located within the “acoustic shadow” of the obstruction, such as behind a sound wall. This type of sound attenuation is known as “barrier insertion loss.” If a 1 All sound levels measured in decibel (dB) in this study are relative to 2x10-5 N/m2. 2 Engineering Noise Control, Bies & Hansen, 1988.
3 Caltrans, “Technical Noise Supplement (TeNS)”, 2013.

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Figure 1. Project Site Map
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Table 1. Typical Noise Levels
Common Outdoor Activities
Noise Levels,
dBA Common Indoor Activities
110 Rock Band
Jet Fly-over at 1000 feet
100
Gas Lawn Mower at 3 feet
90 Diesel Truck at 50 feet at 50 mph Food Blender at 3 feet 80 Garbage Disposal at 3 feet
Noisy Urban Area, Daytime
Gas Lawn Mower at 100 feet 70 Vacuum Cleaner at 10 feet Commercial Area Normal Speech at 3 feet
Heavy Traffic at 300 feet 60
Large Business Office
Quiet Urban Daytime 50 Dishwasher Next Room
Quiet Urban Nighttime 40 Theater, Large Conference Room (background) Quiet Suburban Nighttime
30 Library
Quiet Rural Nighttime Bedroom at Night, Concert Hall (background) 20 Broadcast/Recording Studio (background)
10 Lowest Threshold of Human Hearing 0 Lowest Threshold of Human Hearing Source: Caltrans, Technical Noise Supplement (TeNS), 2013 receptor is located behind the wall but still has a view of the source (i.e., acoustic line-of-sight is not fully blocked), some barrier insertion loss would still occur, however to a lesser extent.

Additionally, a receptor located on the same side of the wall as a noise source may experience an increase in the perceived noise level as the wall reflects noise back to the receptor, thereby compounding the noise. Outdoor sound walls can provide noise level reductions ranging from approximately 5 dBA (where the barrier just breaks the acoustic line-of-sight between the noise source and receiver) to an upper range of 20 dBA with a more substantial barrier.4

2.1.2 Environmental Noise Descriptors
Several rating scales have been developed to analyze the adverse effect of community noise on people. Since environmental noise fluctuates over time, these scales consider the total acoustic 4 Caltrans, “Technical Noise Supplement (TeNS)”, 2013.

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energy content, as well as the time and duration of occurrence. The most frequently used noise descriptors, including those used by the City of Lake Forest, are summarized below.

Equivalent Sound Level (Leq). Leq is a measurement of the acoustic energy content of noise averaged over a specified period. Thus, the Leq of a time-varying sound and that of a steady sound are the same if they deliver the same amount of energy to the receptor’s ear during exposure. Leq for one-hour periods, during the daytime or nighttime hours, and 24 hours are commonly used in environmental noise assessments. Leq can be measured for any period but is typically measured for an increment of no less than 15 minutes for environmental studies.

For evaluating community impacts, this rating scale does not vary, regardless of whether the noise occurs during day or night.

Sound Exposure Level (SEL). SEL is used to evaluate noise effects from the operation of the helistop (i.e., helicopter flight noise) on noise sensitive land uses such as residential. SEL is an energy-based sum of the noise experienced during a single noise event, normalized to one second duration.

Community Noise Equivalent Level (CNEL). CNEL is the time average of all A-weighted sound levels for a 24-hour period with a 10 dBA adjustment (upward) added to the sound levels that occur between the hours of 10:00 P.M. and 7:00 A.M. (nighttime), and a 5 dBA adjustment (upward) added to the sound levels which occur between the hours of 7:00 P.M. and 10:00 P.M. (evening). These penalties attempt to account for increased human sensitivity to noise during the nighttime and evening periods, particularly where sleep is the most probable activity.

CNEL has been adopted by the State of California to define the community noise environment for development of the community noise element of a General Plan.5

2.2 Ground-borne Vibration
Vibration is commonly defined as an oscillatory motion through a solid medium in which the motion’s amplitude can be described in terms of displacement, velocity, or acceleration. The peak particle velocity (PPV) or the root-mean square (RMS) velocity is usually used to describe vibration amplitudes. PPV is defined as the maximum instantaneous peak of the vibration signal and is typically used for evaluating potential building damage.6 The RMS velocity is
defined as the square-root of the average of the squared amplitude of the vibration signal and is typically more suitable for evaluating human response to ground-borne vibration.7 The RMS
vibration velocity level can be presented in inch per second or in VdB (a decibel unit referenced 5 State of California, General Plan Guidelines, 2003.
6 Vibration levels described in this report are in terms peak particle velocity level in the unit of inches per second.
7 Federal Transit Administration (FTA), “Transit Noise and Vibration Impact Assessment,” Section 5.1, September 2018.

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to 1 micro-inch per second).8 Ground-borne vibration generated by man-made activities (e.g., road traffic, construction operations) typically weakens with greater horizontal distance away from the source of the vibration.

2.3 Applicable Noise Standards
Government agencies have established noise standards and guidelines to protect citizens from potential hearing damage and other adverse physiological and social effects associated with noise. The City of Lake Forest General Plan establishes exterior noise standards and guidelines for compatibility with land use and includes number of goals, objectives, and policies for land use planning purposes. The City also has regulations to control excessive and annoying noise, as set forth in the City of Lake Forest Municipal Code (LFMC) Chapter 11.16. Standards and guidelines that may be applicable to this Project are discussed below.

2.3.1 City of Lake Forest General Plan
The overall purpose of the General Plan Noise Element is to guide policy makers in making land use determinations and in preparing noise ordinances that would limit exposure of citizens to excessive noise levels. The following policies and objectives from the City of Lake Forest General Plan Public Safety Element are applicable to the Project:9 PS-6 Policies
PS-6.1 Land Use Planning. Require development and infrastructure projects to be consistent with the maximum allowable noise exposure criteria identified in Table PS-1 to ensure acceptable noise levels for future development.

PS-6.2 Noise-Sensitive Land Uses. Ensure appropriate features are incorporated into the design of noise-sensitive land uses to prevent unacceptable noise exposure.

PS-6.3 Site Design. Require site planning and project design techniques to minimize noise impacts adjacent to sensitive uses in order to comply with City standards.

PS-6.4 Noise Control. Ensure that noise levels do not exceed the limits established in the Municipal Code by incorporating sound-reduction design in new construction and retrofit projects impacted by non-transportation-related noise sources.

PS-6.5 Roadway Noise. Encourage nonmotorized transportation alternatives for local trips and the implementation of noise sensitivity measures in the public realm, including 8 VdB (velocity level in decibel) = 20 x Log (V / Vref), where V is the RMS velocity amplitude in micro-inch per second and Vref is the reference velocity amplitude of 1x10-6 inch per second (1 micro-inch per second). 9 City of Lake Forest General Plan 2024, Public Safety Element, Adopted June 2020.

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traffic-calming road design, lateral separation, natural buffers, and setbacks to decrease excessive motor vehicle noise.

PS-6.8 Commercial Noise. Require the use of noise attenuation measures, including screening and buffering techniques, for all new commercial development expected to produce excessive noise; in existing cases where the City's noise standards are exceeded, work with Code Enforcement to require compliance.

Table 2. City of Lake Forest Land Use Compatibility for Community Noise Environment
Land Use
Outdoor Activity
Areas
Ldn, dBA
Interior Spaces
Ldn, dBA Leq, dBA
Residential 60 45 --
Motels/Hotels 65 45 --
Mixed-Use 65 45 --
Hospitals, Nursing Homes 60 45 --
Theatres, Auditoriums -- -- 35
Places of Worship 60 -- 40
Office Buildings 65 -- 45
Schools, Libraries, Museums 70 -- 45
Playgrounds, Neighborhood Parks 70 -- --
Industrial 75 -- 45
Golf Courses, Water Recreation 70 -- --
Source: City of Lake Forest General Plan, Public Safety Element, Table PS-1.

1. Where a proposed use is not specifically listed, the use shall comply with the criteria for the most similar use as determined by the City.

2. Outdoor activity areas for residential developments are considered to be the private exterior living area of single-family homes and the main common areas where people generally congregate for multi-family and residential components of mixed-use developments. Outdoor activity areas for nonresidential developments are the common areas where people generally congregate, including community centers, pool areas, and outside lunch facilities. New multi-family developments and residential components of mixed-use developments with balconies or patios that are exposed to noise that exceeds the outdoor criteria in this table are required to provide occupancy disclosure notices to all future tenants regarding potential noise impacts.

3. In areas where it is not possible for a new project to reduce exterior noise levels to achieve the outdoor activity area criteria using a practical application of the best noise-reduction technology, as determined by a qualified acoustician, an increase of up to 5 CNEL over the outdoor standard will be allowed provided that available exterior noise reduction measures have been implemented and interior noise levels are in compliance with this table.

4. Determined for a typical operating hour during periods of use.

5. In accordance with Policy PS-6b, this table shall be used for land use compatibility noise criteria for when making planning and development decisions. These criteria represent the acceptable noise level for new sensitive receptors. These criteria are not to be retroactively applied for existing uses.

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These criteria are also not generally intended for use as CEQA significance thresholds for noise generated by new projects to existing receptors; that purpose is achieved by compliance with Municipal Code standards.

6. Abbreviations dBA = A-weighted decibels; Ldn = Day-Night Average Level; Leq = equivalent noise level.

PS-6 Actions
PS-6b To ensure that noise does not adversely affect new sensitive receptors, the City will use land use compatibility noise criteria for various land use types in Table PS-1 when making planning and development decisions. The criteria in Table PS-1 represent the acceptable noise level for new sensitive receptors.

Existing and future noise contours from transportation noise in the City are provided in Figure 1 and Figure 2. The future noise contours in Figure 2 will be used as a guide for land use and development decisions. If the noise level at a project does not exceed the outdoor activity area allowable noise level in Table PS-1, the project is considered compatible with the noise environment.

If the project will exceed the allowable outdoor activity area and interior space noise levels in Table PS-1, the project proponent shall be required to demonstrate ( with an acoustical analysis) that the project is designed to attenuate noise to meet the criteria in Table PS-1, and California Building Standards Code, and California Green Building Standards Code (Title 24) interior noise standards. If the project is not designed to meet the noise criteria, noise reduction measures may be recommended in the analysis. If the analysis demonstrates that the noise criteria can be met with implementation of the noise reduction measures, the project may be approved with the noise reduction measures required as conditions of project approval.

PS-6c To ensure that noise from new development does not adversely affect existing sensitive receptors, the City will require acoustical studies for all new discretionary projects, including those related to development and transportation, which have the potential to generate stationary noise impacts which exceed the criteria identified in the Municipal Code. The studies shall include existing ambient noise measurements, estimates of projected noise levels, and noise reduction measures necessary to ensure compliance with this element.

PS-6d In making a determination of traffic noise impacts under the California Environmental Quality Act CEQA), a significant impact will occur if ambient noise levels have a substantial increase and the resultant noise levels are in excess of the City’s criteria.

Generally, a 3 A-weighted decibel dBA) increase in noise levels is barely perceptible.

Therefore, increases in noise levels shall be considered significant when the following occurs:

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 When existing noise levels are between 60 dBA and 65 dBA CNEL, a 3 dBA CNEL increase in noise will be considered significant.
 When existing noise levels exceed 65 dBA CNEL, a 1.5 dBA CNEL increase in noise will be considered significant.

2.3.2 City of Lake Forest Municipal Code
The following sections of the City of Lake Forest Municipal Code, partially or entirely, may be applicable to the Project:

11.16.040 Exterior Noise Standards
A. The following exterior noise standards set limits for noise that land uses are allowed to generate as received by other land uses. These standards may be used during Code enforcement of potential noise violations. For purposes of determining potential project impacts during environmental impact review processes pursuant to CEQA, the average hourly level (Leq) standards shall be utilized unless all sources are impact in nature. The standards shall apply to the corresponding land use in Residential and Mixed-Use zones only. It is unlawful for any person to create any noise either within or outside the City due to a Stationary Noise Source (or any Mobile Noise Source not pre-empted by State or Federal laws), or to allow the creation of any noise on property owned, leased, occupied, or otherwise controlled by such person, which causes the Noise Level when measured at the property line of any residential use in a residential or mixed use zone, to exceed the applicable noise standards listed in Table 1 – Exterior Noise Standards (as provided in Table 3 (on page 13, below) of this Study).

B. In the event the alleged offensive noise consists entirely of impulsive noise, simple tone noise, amplified speech, music, or any combination thereof, each of the above noise levels shall be reduced by five dBA. Such noises are generally considered to be particularly annoying and are a primary source of noise complaints.

C. If the alleged offense affects a property outside the City's jurisdiction, the exterior noise standards shall be enforced at the City boundary.

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Table 3. City of Lake Forest Exterior Noise Standards
Land Use
Time Interval Noise Level
(dBA Leq)
Noise Level
(dBA Lmax)
Residential in Residential Zones 7:00 a.m. – 10:00 p.m. 60 80 10:00 p.m. – 7:00 a.m. 50 70
Residential Portion of MixedUse in Mixed-Use Zones
7:00 a.m. – 10:00 p.m. 65 85
10:00 p.m. – 7:00 a.m. 50 70
Places of Worship, Hospitals,
and Schools in Residential and
Mixed-Use Zones
All Hours 65 85
Places of Worship, Hospitals,
and Schools in Residential and
Mixed-Use Zones
All Hours 70 90
Source: City of Lake Forest Municipal Code, Section 11.16.040, Table 1.

D. In the event the measured ambient noise level exceeds any of the noise limit categories above, the noise limit as applied to the contribution of the source(s) in question shall be the ambient noise level.

E. If the noise source and the affected property are within different land use categories, the noise standards of the affected property shall apply.

F. For mixed-use residential land uses affected by noise on the same property (e.g., commercial sources affecting the residential portion of the same property), the exterior noise standard shall be applicable at exterior areas provided for private or common usable open space purposes. Private usable open space is defined as usable open space intended for use by occupants of one dwelling unit, normally including yards, decks, and balconies.

Common usable open space is defined as open space intended for common use by any/all residents of a development, including swimming pools, recreation courts, patios, open landscaped areas, and greenbelts with pedestrian walkways and bicycle trails, but not including off-street parking and loading areas or driveways. If no balcony or private open space is provided for a residential unit, the noise limit shall be applicable at the exterior of accessible openings (doors and windows) to the unit.

11.16.050 Exemptions
D. Noise sources associated with Construction, repair, remodeling, or grading of any real property, provided that: (1) the City has issued a building permit, grading permit, or similar permit for such activities; (2) said activities do not take place between the hours of 8:00 p.m. and 7:00 a.m., Monday through Saturday, or at any time on Sunday or a legal City of Lake Forest holiday; and (3) the average construction noise levels do not exceed 80 dBA Leq at the first floor of nearby noise-sensitive residential uses.

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E. Noise sources associated with solid waste collection and removal, provided such activities take place in accordance with LFMC Section 16.05.000(D).

11.16.080 Construction
The following regulations established hours, allowed maximum noise levels, and best management practices for construction noise that occurs within the City of Lake Forest. These standards may be used during code enforcement of potential noise violations or used to determine potential project impacts during environmental review processes pursuant to the California Environmental Quality Act ("CEQA"). The following is required for construction:

A. Construction activities, including delivery of material or equipment, shall not take place between the hours of 8:00 p.m. and 7:00 a.m., Monday through Saturday, or at any time on Sunday or a City holiday; and the average construction noise levels shall not exceed 80 dBA Leq (one-hour) on the first floor of nearby noise-sensitive land uses.

B. If construction noise has the potential to exceed the standards in Section 11.16.090(A), as determined by code enforcement of noise violations, analysis of potential construction noise impacts during a review pursuant to the California Environmental Quality Act, or if construction using heavy equipment is proposed within 100 feet of noise-sensitive land uses, a construction noise management plan shall be prepared by a qualified acoustician and submitted by the applicant. The noise reduction measures shall be determined in the plan and shall be quantified to demonstrate that noise levels would not exceed the standards.

11.16.090 Vibration
A. Operating or permitting the operation of any device that creates vibration that exceeds current published Caltrans vibration criteria at a receiving vibration-sensitive land use is prohibited.

B. For projects implementing a phase or phases of construction that incorporate equipment as presented in Table 2 below: during the pre-building permit issuance phase and after a specific equipment list has been determined: (1) a qualified structural engineer, as approved by the Director of Community Development, or designee, shall identify all structures that are located within the distances established in Table 2 and that have the potential to be affected by ground-borne vibration originating from the construction; and (2) a qualified acoustical engineer shall compile a list of proposed construction equipment and compare to the City's accepted vibration criteria. If it is determined that the proposed equipment would generate vibration levels below the City's standard of 0.3 inches per second (in/sec) peak particle velocity (PPV), no further vibration assessment is necessary. However, if vibration levels would potentially exceed the City's standard of 0.3 in/sec PPV, the project applicant shall develop a vibration monitoring and construction contingency plan for Item: 11
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approval by the Director of Community Development, or designee, to ensure that vibration levels would not exceed the City's accepted vibration damage criteria of 0.3 in/sec PPV. If a vibration monitoring and construction contingency plan is deemed necessary, monitoring of vibration during initial construction activities shall be required. Monitoring results may indicate the need for more or less intensive measurements. The vibration monitoring and construction contingency plan, at the discretion of the Director of Community Development or designee, shall include the following items as necessary:

1. Identification of structures where monitoring would be conducted.

2. A vibration monitoring schedule.

3. Defined structure-specific vibration limits.

4. Photographic, elevation, and crack surveys to document before and after construction conditions; and

5. Identification of construction contingencies for when vibration levels approach the limits. When vibration levels approach the limits specified in this chapter, construction shall be suspended and contingencies identified in the approved vibration monitoring and construction contingency plan shall be implemented as necessary to lower vibration levels. For some projects, the ability to shield or protect the affected building from potential vibration impacts may be possible as an alternative to changing construction methods.

Table 4. City of Lake Forest Vibration Assessment Guidelines Phase of Construction Distance (ft)
Grading
- Large equipment
* Example: D9 dozer, loaded dump truck
15 - Impact hand tools
* Example: Jackhammer
10 Pile Driving
- Impact pile driver 300 or within 5 times the depth of the pile, whichever is less
- Vibratory pile driver 150 or within 5 times the depth of the pile, whichever is less
Source: City of Lake Forest Municipal Code, Section 11.16.090, Table 2.

2.4 Applicable Vibration Standards
The Federal Transit Administration (FTA) has published a technical manual titled, “Transit Noise and Vibration Impacts Assessment,” that provides ground-borne vibration impact criteria Item: 11
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with respect to building damage during construction activities.10 Table 5 (below) provides the vibration criteria (based on FTA) applicable to construction activities. According to FTA guidelines, a vibration criterion of 0.2 PPV should be considered as the significant impact level for non-engineered timber and masonry buildings. Structures or buildings constructed of reinforced concrete, steel, or timber, have a vibration damage criterion of 0.5 PPV, and structures that are extremely susceptible to vibration damage have a vibration damage criterion of 0.12 PPV, pursuant to the FTA guidelines. Although the LFMC Section 11.16.090 refers to Caltrans vibration criteria, the Project vibration impact analysis is based on the FTA vibration criteria, per the City of Lake Forest CEQA Significance Thresholds Guide, which has been recently updated and adopted in May 2025.11
Table 5. FTA Construction Vibration Impact Criteria for Building Damage Building Category
Peak Particle Velocity (PPV),
(in/sec)
I. Reinforced-concrete, steel or timber (no plaster) 0.5 II. Engineered concrete and masonry (no plaster) 0.3
III. non-engineered timber and masonry buildings 0.2
IV. Buildings extremely susceptible to vibration damage 0.12 Source: FTA, 2018
In addition, the FTA guidance manual also provides vibration criteria for human annoyance for various uses. These criteria were established primarily for rapid transit (rail) projects and, as indicated in Table 6 (below), are based on the frequency of vibration events. Specific criteria are provided for three land use categories: (1) Vibration Category 1—High Sensitivity; (2) Vibration Category 2—Residential; and (3) Vibration Category 3—Institutional.

Table 6. FTA Construction Vibration Impact Criteria for Human Annoyance Land Use Category
Ground-Borne Vibration Impacts Levels (VdB)
Frequent
Eventsa
Occasional
Eventsb
Infrequent
Eventsc
Category 1: Building where vibration would
interfere with interior operations
65d 65d 65d
Category 2: Residences and buildings where
people normally sleep
72 75 80
Category 3: Institutional land uses with
primarily daytime uses
75 78 83
a “Frequent Events” are defined as more than 70 vibration events of the same source per day. b “Occasional Events” are defined as between 30 and 70 vibration events of the same source per day. 10 FTA, “Transit Noise and Vibration Impact Assessment,” September 2018. 11 City of Lake Forest, Resolution No. 2025-11, adopted May 6th, 2025. Appendix 1 City of Lake Forest CEQA Significance Thresholds Guide, Section 3.4, Revised 2025.

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Land Use Category
Ground-Borne Vibration Impacts Levels (VdB)
Frequent
Eventsa
Occasional
Eventsb
Infrequent
Eventsc
c
“Infrequent Events” are defined as fewer than 30 vibration events of the same source per day. d This criterion limit is based on the levels that are acceptable for most moderately sensitive equipment such as optical microscopes.

Source: FTA, 2018

2.5 Existing Ambient Noise Levels
Some land uses are considered more sensitive to intrusive noise than others based on the types of activities typically involved at the receptor location. Based on a review of the land uses in the Project area, a total of six noise sensitive receptor locations were selected to represent nearest noise sensitive uses (including residential and school) surrounding the Project site. The locations of the six noise-sensitive receptors are identified as R1 through R6 in Figure 2 (on page 18). Descriptions of the noise receptor locations are provided in Table 7 (below).

Table 7. Description of Noise Receptor Locations
Location
General Description of Measurements
Locations
Approximate
Distance to
Project Site,a
Feet
Representing
Nearby Land Uses
R1 Multi-family residential uses located on the
north side of Alton Parkway, north of the
Project Site
1,570 Residential
R2 Single-family residential uses located at the
cul-de-sac of Blanco, northeast of the
Project Site
1,910 Residential
R3 Multi-family residential uses located on the
south side of Bake Parkway, southeast of
the Project Site
1,610 Residential
R4 Single-family residential uses located on
the north side of Newton, southwest of the
Project Site
2,015 Residential
R5 Multi-family residential uses located on the
south side of Indigo Place, northwest of the
Project Site
665 Residential
R6 Guidepost Montessori and Alpha School
Lake Forest, located at 26462 Towne
Centre Drive, north of the Project Site
760 School
a Approximate distance from property line to property line, as measured using Google Earth map.

Source: AES, 2025

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Source: Google Earth Map, 2025
Figure 2. Noise Receptor Locations
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The ambient noise monitoring program was conducted using a Larson-Davis Model 870 Integrating/Logging Sound Level Meters, the sound level meter meets the minimum industry standard performance requirements for “Type 1” standard instruments as defined in the American National Standard Institute (ANSI) S1.4. Two 15-minute measurements, one during the daytime hours (between 10 a.m. and 12 p.m.) and another during the nighttime hours (between 10 p.m. and 12 a.m.), were conducted at the off-site receptor locations, on July 14, 2025.

Table 8 (below) presents the measured ambient noise levels at the selected noise receptors located in the close vicinity of the Project site, in Leq (average sound level). Based on field observation and measured sound data, the current ambient noise environment in the vicinity of the Project Site is controlled primarily by vehicular traffic on nearby roadways (i.e., Alton Parkway, Portola Parkway, Bake Parkway, Towne Centre Drive, and CA-241 Freeway). As indicated in Table 8, the existing daytime ambient noise levels ranged from 43.7 dBA Leq at receptor R2 to 63.8 dBA Leq at receptor R3. The existing nighttime ambient noise levels ranged from 37.6 dBA Leq at receptor R4 to 53.7 dBA Leq at receptor R3. The existing ambient noise levels are below the City’s exterior noise standards of 60 dBA Leq during daytime hours and 50 dBA Leq during the nighttime hours.

Table 8. Existing Ambient Noise Levels
Location Noise-Sensitive Land Use
Measured Ambient Noise Levels,
dBA Leq
Daytime
Hours(between 10
a.m. and 12 p.m.)
Nighttime
Hours(between 10
p.m. and 12 a.m.)
R1 Residential 52.6 48.5
R2 Residential 43.7 41.5
R3 Residential 63.8 53.7
R4 Residential 50.9 37.6
R5 Residential 49.4 44.3
R6 School 50.0a 40.0a
a
Estimated based on nearby measurements.

Source: AES, 2025, See Appendix A for detail ambient noise measurements data.

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3 IMPACT ANALYSIS

3.1 Methodology

3.1.1 Construction Noise
Construction noise impacts due to on-site construction activities associated with the Project were evaluated by calculating the construction-related noise levels at representative sensitive receptor locations and comparing these estimated construction-related noise levels to the existing ambient noise levels (i.e., noise levels without construction noise from the Project).

Construction noise associated with the Project was analyzed based on the Project’s potential construction equipment inventory, construction durations, and construction schedule. The construction equipment noise levels are based on the published noise data (equipment source levels) by the FHWA “Roadway Construction Noise Model (FHWA 2006).” The construction noise levels were then calculated for sensitive receptor locations based on the standard point source (e.g., generator or bulldozer) noise-distance attenuation factor of 6 dBA for each doubling of distance. Additional noise attenuation was assigned to receptor locations where the line-of-sight to the Project Site was interrupted by the presence of intervening structures.

For the noise analysis, a 5 dBA attenuation was assigned for receptor locations where the acoustic line-of-sight is just interrupted (i.e., around the edge of a building) and up to 15 dBA for receptor locations where the acoustic line-of-sight is fully interrupted (i.e., by intervening buildings).

3.1.2 Construction Vibration
Ground-borne vibration impacts due to the Project’s construction activities were evaluated by identifying potential vibration sources (i.e., construction equipment), estimating the vibration levels at the potentially affected receptors (building structures), and comparing the Project’s activities to the applicable vibration significance thresholds, as described below.

Vibration levels were calculated based on the FTA published standard vibration velocities for various construction equipment operations.12 The vibration velocities were calculated based on a point source with standard distance propagation conditions, pursuant to FTA procedures.

Construction of the Project would not use impact pile driving methods and as such, impact pile driving vibration is not included in this construction vibration analysis.

3.1.3 Operational Noise
On-site stationary point-source noise impacts were evaluated by (1) identifying the noise levels that would be generated by the Project’s on-site noise sources, including mechanical equipment, loading dock operations, warehouse delivery trucks, trash compactors, parking lot operations, and tire installation center, (2) calculating the noise level from each noise source at 12 FTA, “Transit Noise and Vibration Impact Assessment,” Table 7-4, September 2018.

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surrounding sensitive receptor property line locations; and (3) comparing such noise levels to ambient noise levels to determine significance. The on-site stationary noise sources were calculated using SoundPLAN (version 8.2), a 3-dimensional computer noise prediction model, which calculates noise transference (propagation) using approved engineering procedures and incorporates national and international noise standards. This calculation tool is widely used by acoustic engineers as a noise modeling tool for environmental noise analysis. In addition, the SoundPLAN utilizes the FHWA’s TNM 2.5 (FHWA and Caltrans official traffic noise model) for traffic noise calculations.

Potential noise impacts due to Project-related off-site traffic were analyzed by calculating the increase in noise levels associated with the increase in traffic volumes. Traffic noise levels were calculated using the Federal Highway Administration (FHWA) Traffic Noise Model (TNM) and traffic volume data from the traffic generation analysis prepared for the Project.13 The TNM traffic noise prediction model calculates the hourly Leq noise levels based on specific information including the hourly traffic volume, vehicle type mix, vehicle speed, and lateral distance between the noise receptor and the roadway. To calculate the 24-hour CNEL levels, the hourly Leq levels were calculated during daytime hours (7:00 a.m. to 7:00 p.m.), evening hours (7:00 p.m. to 10:00 p.m.), and nighttime hours (10:00 p.m. to 7:00 a.m.). The traffic noise prediction model calculates the 24-hour CNEL noise levels based on specific information, including Average Daily Traffic (ADT); percentages of day, evening, and nighttime traffic volumes relative to ADT; vehicle speed; and distance between the noise receptor and the roadway. The calculated CNEL levels are conservatively calculated in front of the roadways and do not account for the presence of any physical sound barriers or intervening structures.

3.2 Significance Thresholds
In accordance with the State CEQA Guidelines Appendix G, the Project would have a significant impact related to noise if it would result in the:

Threshold (a): Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies.

Threshold (b): Generation of excessive groundborne vibration or groundborne noise levels.

Threshold (c): For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles 13 Kittelson & Associates, Inc., Foothill Ranch Costco Focused Transportation Impact Study, September 2025.

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of a public airport or public use airport, expose people residing or working in the project area to excessive noise levels.

The Project significance thresholds are based on the City’s General Plan and Municipal Code as described above, and the City’s CEQA Significance Thresholds Guide14.

3.2.1 Construction Noise
The project would normally have significant construction noise impacts if it would:
 Exceed 80 dBA Leq(1-hour) between the hours of 7:00 a.m. and 8:00 p.m., Monday through Saturday.15

3.2.2 Construction Vibration
Per the City’s CEQA Significance Thresholds Guide, the project would normally have a significant vibration impacts if it would exceed the applicable standards from the FTA or Caltrans. Therefore, based on FTA standards as described above, the project would result in significant vibration impacts if:
 Project construction activities cause ground-borne vibration levels to exceed 0.5 PPV at the nearest off-site non-engineered timber and masonry building (typical woodframe buildings).  Project construction activities cause ground-borne vibration levels to exceed 75 VdB at off-site residential uses or 78 VdB at off-site school uses.

3.2.3 Operations Noise
The operational noise impacts would be considered significant if:
 The noise level generated by on-site noise sources would exceed the City’s exterior noise standards or the measured ambient noise levels, whichever is greater, as follows:
o At residential uses: 60 dBA (Leq) during the daytime hours (between 7:00 a.m. and 10:00 p.m.) and 50 dBA (Leq) during the nighttime hours (between 7:00 a.m. and 10:00 p.m.).
14 https://cms2.revize.com/revize/lakeforest/Documents/Departments/Community%20Development/Plann ing/Plans%20and%20Standard%20Guidelines/CEQA%20Guidelines/CEQA-Significance-ThresholdsGuide-2025-Transpo-Analysis-Guidelines-05-06-25.pdf?t=202508141138130&t=202508141138130 15 Per the City, construction is prohibited between 8:00 p.m. and 7:00 a.m., Monday through Saturday, or at any time on Sunday or a City holiday.

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o At school site uses: 65 dBA (Leq) at all hours.
 The noise level generated by off-site traffic results in:
o An increase the 3 dBA CNEL when the existing noise levels are between 60 dBA and 65 dBA CNEL, or
o An increase of 1.5 dBA CNEL when the existing noise levels exceed 65 dBA CNEL.

3.3 Construction Noise Impacts
Noise impacts from Project construction activities would be a function of the noise generated by construction equipment, the location of the equipment, the timing and duration of the noisegenerating construction activities, and the relative distance to noise-sensitive receptors.

Construction activities for the Project would generally include demolition, site grading and excavation, building construction, and landscaping. Each stage of construction would involve the use of various types of construction equipment and would, therefore, have its own distinct noise characteristics. Demolition would involve the use of excavators, breakers, backhoes, and heavy-duty trucks. Grading and excavation would require the use of graders, excavators, breakers, jackhammers, backhoes, compactors, and heavy-duty trucks. Building construction would involve the use of air compressors, cranes, concrete trucks, paving trucks, compactors, and delivery trucks. Landscaping would involve the use of backhoes and work trucks. Noise from construction equipment would generate both steady-state and episodic noise that could be heard within and adjacent to the Project Site.

Individual pieces of construction equipment that would be used for construction of the Project produce maximum noise levels of 75 dBA to 90 dBA at a reference distance of 50 feet from the noise source, as shown in Table 9 (on page 24). The construction equipment noise levels at 50 feet distance (Referenced Maximum Noise Levels) are based on the FHWA Roadway Construction Noise Model User’s Guide (RCNM, 2006), which is a technical report containing actual measured noise data for construction equipment. These maximum noise levels would occur when equipment is operating under full power conditions (i.e., the equipment engine at maximum speed). However, equipment used on construction sites often operates under less than full power conditions, or part power. To more accurately characterize construction-period noise levels, the average (Hourly Leq) noise level associated with each construction stage is calculated based on the quantity, type, and usage factors for each type of equipment that would Item: 11
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be used during each construction stage.16,17 These noise levels are typically associated with multiple pieces of equipment operating simultaneously.

Table 9. Typical Construction Equipment Noise Emission Levels and Usage Factors Type of Equipment
Acoustical Usage Factora
(%)
Reference Maximum Noise
Levels at 50 Feet,b Lmax
(dBA)
Air Compressor 40 78
Backhoe 40 78
Cement and Mortar Mixers 50 80
Concrete Mixer Truck 40 79
Concrete Saw 20 90
Crane 16 81
Dozer 40 82
Dump/Haul Truck 40 76
Excavator 40 81
Forklift 20 75
Generator 50 81
Loader 40 79
Paving Equipment 50 77
Rollers 20 80
Tractors/Loaders/Backhoes 40 84
Water Truck 10 82
Welders 40 74
a The usage factor is the estimated percentage of time during an 8-hour day that a piece of construction equipment is operating at full power.
b Construction equipment noise levels are based on the FHWA RCNM.

Source: FHWA Roadway Construction Noise Model User’s Guide, Table 1, 2006 Construction, generally, would start with the demolition of existing structures, follow by site preparation and grading, building construction, paving/landscaping, and architectural coating.

Table 10 (on page 26) provides the estimated, unmitigated construction noise levels at the offsite noise sensitive receptors by construction phase. To present a conservative noise impact analysis, the estimated noise levels were calculated with all pieces of construction equipment assumed to be operating simultaneously and located at the construction area nearest to the 16 Pursuant to the FHWA Roadway Construction Noise Model User’s Guide, 2005, the usage factor is the percentage of time during a construction noise operation that a piece of construction is operating at full power.
17 Construction noise levels are calculated in terms of hourly Leq consistent with the City’s exterior noise limits.

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affected receptors. As indicated in Table 10, the estimated construction noise levels would be below the Project significance threshold (80 dBA) at all off-site noise receptors.

The construction phases of the Project would have the potential to overlap. Therefore, overlapping construction noise activities were evaluated to determine the potential impacts.

Construction noise impacts associated with the overlapping construction are provided in Table 11 (on page 26). As indicated in Table 11, the estimated noise levels due to overlapping construction activities would be below the Project significance threshold (80 dBA) at all offsite receptor locations. Therefore, temporary noise impacts associated with the Project’s onsite construction would be less than significant.

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Table 10. On-Site Construction Noise Impacts
Receptor
Location
Estimated Construction Noise Levels by Phase, dBA (Leq) Significance Threshold,a
dBA (Leq)
Sig.

Demolition Site Prep Grading Impacts?
Building
Construction Paving
Architectural
Coating
R1 55.6 59.3 60.3 56.1 53.1 44.1 80.0 NoR2 54.0 58.3 59.2 54.5 52.1 42.4 80.0 No R3 51.8 55.4 56.3 50.9 49.2 38.9 80.0 NoR4 50.8 51.8 52.8 49.0 45.6 36.9 80.0 No R5 63.1 66.3 67.2 63.2 60.2 51.5 80.0 No R6 60.6 68.3 68.8 62.0 61.8 50.4 80.0 No a Significance thresholds are equivalent to the City’s daytime construction noise limits of 80 dBA.

Source: AES, 2025.

Table 11. On-Site Construction Noise Impacts – Over lapping Construction Receptor
Location
Estimated Construction Noise Levels by Phase, dBA (Leq) Significance
Threshold,a
dBA (Leq)
Significant
Impacts?
Grading +
Building
Construction
Building
Construction +
Paving
Building
Construction +
Paving +
Architectural
Coating
R1 61.7 57.9 58.0 80.0 NoR2 60.5 56.5 56.6 80.0 No R3 57.4 53.1 53.3 80.0 NoR4 54.3 50.6 50.8 80.0 No R5 68.7 65.0 65.2 80.0 No R6 69.6 64.9 65.1 80.0 No a Significance thresholds are equivalent to the City’s daytime construction noise limits of 80 dBA.

Source: AES, 2025.
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3.4 Construction Vibration Impacts
Construction activities can generate varying degrees of ground vibration, depending on the construction procedures and the type of construction equipment used. The operation of construction equipment generates vibrations that travel through the ground and diminish in amplitude with distance from the source. The effect on buildings located in the vicinity of the construction site often varies, depending on soil type, ground strata, and construction characteristics of the receptor buildings.

Regarding potential building damage, the Project would generate ground-borne construction vibration forces during the demolition, site preparation, grading, and paving phases when heavy construction equipment, such as vibratory rollers, large bulldozers, and loaded trucks, would be used. The FTA has published standard vibration velocity levels for various construction equipment operations. Table 12 (below) presents the typical vibration levels at a reference distance of 25 feet for construction equipment anticipated to be used during Project construction. Vibration impacts regarding structures are evaluated at the nearest off-site buildings to the Project Site (commercial buildings to the north, south, east and west), whereas the potential for human annoyance associated with construction-related vibration are evaluated at the six human annoyance vibration-sensitive receptor locations (i.e., receptor locations R1 through R6).

Table 12. Construction Equipment Vibration Levels
Equipment
Equipment vibration Levels at 25 feet,
(PPV/VdB)
Vibratory Rollers 0.210/94
Large Bulldozer (e.g., excavators, graders) 0.089/87
Loaded Trucks (e.g., haul trucks) 0.076/86
Jackhammer 0.035/79
Small Bulldozer (e.g., backhoe) 0.003/58
Source: FTA, 2018
Table 13 (on page 28) provides the estimated vibration levels (in terms of inch per second PPV) at the nearest off-site structures adjacent to the Project Site. To present a worst-case vibration impact analysis, the estimated vibration levels were calculated with the construction equipment assumed to be operating at the closest distance to the nearest off-site building structures. As indicated in Table 13, the estimated vibration velocity levels from all construction equipment would be below the building damage significance criteria at all off-site building structures. As such, on-site vibration impacts, pursuant to the significance criteria for building damage, during construction of the Project would be less than significant.

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Table 13. Construction Vibration Impacts – Building Damage Nearest Off-Site
Building Structuresa
Estimated Vibration Velocity Levels at the Nearest Off-Site Structures from the Project Construction Equipment,b
inch/second (PPV)
Significance
Threshold,
inch/second
(PPV)
Sig.

Impacts?
Vibratory
Rollerd
Large
Bulldozerd
Loaded
Trucksd
JackhammereSmall
Bulldozerf
Commercial Buildings
to the North

0.031 0.013 0.011 0.005 <0.001 0.50c No
Commercial Buildings
to the East

0.057 0.024 0.020 0.009 0.001 0.50c No
Commercial Buildings
to the South

0.368 0.156 0.133 0.061 0.005 0.50c No
Commercial Buildings
to the West

0.003 0.001 0.001 <0.001 <0.001 0.50c No
a Represents off-site building structures located nearest to the Project Site to the north, south, east and west. b Vibration levels calculated based on FTA reference vibration level at 25-foot distance. c FTA criteria for non-engineered concrete and masonry buildings.

Source: FTA, 2018; AES, 2025
Table 14 (below) presents the estimated vibration velocity levels (in terms of VdB) due to construction equipment at the off-site vibration sensitive receptors. To present a worst-case analysis, the estimated vibration levels were calculated with the construction equipment assumed to be operating at the closest distance to the nearest off-site sensitive receptors. As indicated in Table 14, the estimated vibration levels due to on-site construction equipment would be below the significance threshold for human annoyance at all off-site vibration sensitive receptors. Therefore, on-site vibration impacts, pursuant to the significance criteria for human annoyance, during construction of the Project would be less than significant.

Table 14. Construction Vibration Impacts – Human Annoyance Off-Site
Receptor
Location
Estimated Vibration Velocity Levels at the Nearest Off-Site Sensitive Receptors from the Project Construction Equipment,a
VdB Significance
Threshold,
VdB
Sig.

Impacts?
Vibratory
Rollerc
Large
Bulldozerc
Loaded
Trucksc
JackhammerdSmall
Bulldozere
R1 40 33 32 25 4 75 No
R2 38 31 30 23 2 75 No
R3 40 33 32 25 4 75 No
R4 37 30 29 22 1 75 No
R5 51 44 43 36 15 75 No
R6 50 43 42 35 14 78 No
a Vibration levels calculated based on FTA reference vibration level at 25-foot distance.

Source: FTA, 2018; AES, 2025.

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3.5 Operation Impacts
Operation noise levels associated with the Project would include on-site mechanical equipment, loading dock operation, warehouse delivery trucks, trash compactors, parking lot operation, and the tire installation center; and off-site traffic noise.

3.5.1 Mechanical
The Project would include mechanical equipment (e.g., air ventilation equipment and emergency generator), which would be located at the roof level and/or placed within the building structure. Project-related outdoor mechanical equipment would be designed to comply with the City’s exterior noise standards. Table 15 (below) presents the estimated onsite mechanical equipment noise levels at the off-site receptor locations. As shown on Table 15, the estimated noise levels from the mechanical equipment would range from 30.9 dBA (Leq) at receptor location R2 to 39.4 dBA (Leq) at receptor location R5, which would be well below the Project significance thresholds. As such, noise impacts from the Project mechanical equipment would be less than significant.

Table 15. Mechanical Noise Levels
Receptor
Location
Existing
Ambient
Noise Levels,
dBA (Leq)
Estimated Noise
from Mechanical
Equipment,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 48.5 33.1 50.0 0.0 No
R2 41.5 30.9 50.0 0.0 No
R3 53.7 31.7 50.0 0.0 No
R4 37.6 31.4 50.0 0.0 No
R5 44.3 39.4 50.0 0.0 No
R6 40.0 38.3 65.0 0.0 No
Notes:
a Significance threshold equal to City’s nighttime noise limits.

Source: AES, 2025

3.5.2 Loading Dock Operation
The Project includes a loading dock, which is planned to be located at the southeast corner of the warehouse building. The loading dock includes four loading bays. Noise sources associated with the loading dock would include delivery truck loading/unloading of goods.

Based on measured noise levels from typical loading dock facilities, delivery trucks could generate noise levels of approximately 64.7 dBA (Leq) at a distance of 100 feet.18 The noise analysis assumed maximum of four delivery trucks loading/unloading simultaneously to 18 RK Engineering Group, Inc., Wal-Mart/Sam’s Club Reference Noise Level Study, 2003.

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represent a conservative analysis. Table 16 (below) presents the estimated noise levels associated with the loading dock operations at the off-site receptor locations. As shown on Table 16, the estimated noise levels from the loading dock range from 12.8 dBA (Leq) at receptor R2 to 36.8 dBA (Leq) at receptor location R4, which would be well below the Project significance thresholds. Therefore, noise impacts from the loading dock operations would be less than significant.

Table 16. Loading Dock Operation Noise Levels
Receptor
Location
Existing
Ambient
Noise Levels,
dBA (Leq)
Estimated Noise
from Loading
Dock Operation,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 48.5 15.0 50.0 0.0 No
R2 41.5 12.8 50.0 0.0 No
R3 53.7 19.6 50.0 0.0 No
R4 37.6 36.8 50.0 0.0 No
R5 44.3 25.0 50.0 0.0 No
R6 40.0 20.8 65.0 0.0 No
Notes:
a Significance threshold equal to City’s nighttime noise limits.

Source: AES, 2025

3.5.3 Warehouse Delivery Trucks
The warehouse deliveries would take place between 2:00 a.m. and 10:00 a.m. with 14 to 16 deliveries per day, and with maximum two deliveries per hour. The noise analysis assumed the delivery trucks would enter and leaving the Project Site through Portola Parkway and Bake Parkway. Table 17 (on page 31) presents the estimated noise levels associated with the warehouse delivery trucks at the off-site noise sensitive receptors. As indicated in Table 17, the estimated noise levels from the warehouse delivery truck operation range from 26.0 dBA (Leq) at receptor R1 to 49.3 dBA (Leq) at receptor location R3, which would be below the significance threshold. Therefore, noise impacts from the warehouse delivery trucks would be less than significant.

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Table 17. Warehouse Delivery Truck Noise Levels
Receptor
Location
Existing
Ambient
Noise Levels,
dBA (Leq)
Estimated Noise
from Delivery
Trucks,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 48.5 26.0 50.0 0.0 No
R2 41.5 35.6 50.0 0.0 No
R3 53.7 49.3 50.0 0.0 No
R4 37.6 40.9 50.0 0.0 No
R5 44.3 30.2 50.0 0.0 No
R6 40.0 39.3 65.0 0.0 No
Notes:
a Significance threshold equal to City’s nighttime noise limits.

Source: AES, 2026
As presented above, the estimated noise levels associated with warehouse delivery trucks would be below the City’s nighttime noise limit. Furthermore, a noise analysis is carried out to address the potential sleep disturbance using the Sound Exposure Level (SEL). It should be noted that the SEL analysis with respect to potential sleep disturbance is mainly applicable to aviation related noises. Currently, there are no noise standards, or limit, to address traffic noise impacts on sleep (sleep disturbance), using SEL noise descriptor. Therefore, the recommended SEL noise limit from the LAX South Airfield Improvement Project EIR (LAX EIR) was used to evaluate potential sleep disturbance for the Project, which specified a maximum 81 dBA SEL at the interior of the residence.19 Per the LAX EIR, buildings with window open would provide approximately 13 dBA exterior/interior noise reduction. Therefore, based on the interior noise limit of 81 dBA SEL and typical noise reduction of a building with window open of 13 dBA, the maximum exterior noise limit would be 94 dBA SEL, considered threshold for the sleep disturbance to occur. The estimated SEL due to a delivery truck would range from

58.6 dBA SEL at the exterior of receptor R1 (nearest residences to the north) to 81.9 dBA SEL at the exterior of receptor R3 (nearest residence to the east). As analyzed, the estimated SEL levels at the off-site sensitive receptors would be well below the 94 dBA SEL exterior noise limits. In addition, the estimated SEL at the interior of the nearest residences, with the window opens (worst-case noise scenario) would be approximately 45.6 (nearest residences to the north) to 68.9 dBA SEL (residences to the east), which would be below the 81 dBA SEL interior noise limits.
19 LAX Project EIR (https://www.lawa.org/lawa-our-lax/environmental-documents/documents-certified/laxnorthside-plan-update/environmental-documents). Although the Berkeley Jets case ruling directed that the significance of single event noise effects be addressed in an EIR, there was no established basis for defining or assessing the significance of single event aircraft noise, and the Court of Appeal did not set forth any standards of significance in the evaluation of such events.

Item: 11
1892
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026

3.5.4 Trash Compactors
The Project includes two trash compactors located along the east side of the warehouse building. The trash compactors would operate during the daytime hours between 9:30 a.m. and 8:30 p.m. Based on measured noise levels from typical trash compactor, a trash compactor could generate noise levels of approximately 65.5 dBA (Leq) at 50 feet.20 The noise analysis assumed both trash compactors would operate simultaneously to represent a conservative analysis. Table 18 (below) presents the estimated noise levels associated with the trash compactors operation at the off-site receptor locations. As shown on Table 18, the estimated noise levels from the trash compactors range from 8.7 dBA (Leq) at receptor R2 to 41.6 dBA (Leq) at receptor location R5, which would be well below the Project significance thresholds.

Therefore, noise impacts from the trash compactors operation would be less than significant.

Table 18. Trash compactors Operation Noise Levels
Receptor
Location
Existing
Ambient
Noise Levels,
dBA (Leq)
Estimated Noise
from Trash
Compactors,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 52.6 11.4 60.0 0.0 No
R2 43.7 8.7 60.0 0.0 No
R3 63.8 11.0 60.0 0.0 No
R4 50.9 28.9 60.0 0.0 No
R5 49.4 41.6 60.0 0.0 No
R6 50.0 16.2 65.0 0.0 No
Notes:
a Significance threshold equal to City’s daytime noise limits.

Source: AES, 2025

3.5.5 Parking Lot Operation
The Project parking lot includes 913 parking spaces mostly along the eastern and southern sides of the Project Site. Sources of noise within the parking lot would primarily include vehicular movements and engine noise, sounding of doors opening and closing, and people talking.

Noise levels within the parking structure would fluctuate with the amount of automobile and human activity. Table 19 (on page 33) presents the estimated noise levels associated with the parking lot at the off-site receptor locations. As shown on Table 19, the estimated noise levels from the parking lot range from 33.3 dBA (Leq) at receptor R1 to 44.5 dBA (Leq) at receptor location R6, which would be well below the existing ambient noise levels. As such, the estimated noise levels at all off-site receptor locations would be below the significance 20 RK Engineering Group, Inc., Wal-Mart/Sam’s Club Reference Noise Level Study, 2003.

Item: 11
1893
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026
thresholds. Therefore, noise impacts from the parking lot operations would be less than significant.

Table 19. Parking Lot Operation Noise Levels
Receptor
Location
Existing
Ambient
Noise Levels,
dBA (Leq)
Estimated
Noise from
Parking Lot,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 52.6 33.3 60.0 0.0 No
R2 43.7 34.2 60.0 0.0 No
R3 63.8 35.2 60.0 0.0 No
R4 50.9 36.7 60.0 0.0 No
R5 49.4 34.4 60.0 0.0 No
R6 50.0 44.5 65.0 0.0 No
Notes:
a Significance threshold equal to City’s daytime noise limits.

Source: AES, 2025

3.5.6 Parking Lot Cleaning
In addition, the parking lot will be cleaned with a vacuum truck. The parking lot cleaning would typically occur during the early morning or late evening hours (before and after the warehouse open and closed). Reference noise level for a typical vacuum street sweeper, as published by the FHWA RCNM, is approximately 72 dBA (Leq) at 50 feet. Table 20 (below) presents the estimated noise levels associated with the parking lot at the off-site receptor locations. As shown on Table 20, the estimated noise levels from the parking lot range from

34.9 dBA (Leq) at receptor R1 to 46.7 dBA (Leq) at receptor location R6, which would be well below the significance thresholds. Therefore, noise impacts from the parking lot cleaning would be less than significant.

Table 20. Parking Lot Cleaning Noise Levels
Receptor
Location
Existing
Ambient Noise
Levels,
dBA (Leq)
Estimated Noise
from Parking
Lot Cleaning,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 48.5 33.1 50.0 0.0 No
R2 41.5 34.8 50.0 0.0 No
R3 53.7 35.8 50.0 0.0 No
R4 37.6 38.2 50.0 0.0 No
R5 44.3 43.9 50.0 0.0 No
R6 40.0 44.9 65.0 0.0 No
Notes:
a Significance threshold equal to City’s nighttime noise limits.

Source: AES, 2025
Item: 11
1894
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026

3.5.7 Tire Installation Center
The Project includes a member-only tire installation center, located at the west side of the warehouse building. Typical operations within the tire installation center would include various noise sources including wheel balancers, tire changers, air-compressors, and pneumatic tools. Based on previous noise measurements made at a similar Costco facility, operation of the member-only tire installation center would generate average noise levels of approximately 65 dBA (Leq), at a distance of 50 feet from the tire installation center open bay doors.21 Table 21 (below) presents the estimated noise levels associated with the parking lot at the off-site receptor locations. As shown on Table 21, the estimated noise levels from the parking lot range from 9.0 dBA (Leq) at receptor R4 to 32.7 dBA (Leq) at receptor location R6, which would be well below the significance thresholds. Therefore, noise impacts from the tire installation center would be less than significant.

Table 21. Tire Installation Center Noise Levels
Receptor
Location
Existing
Ambient Noise
Levels,
dBA (Leq)
Estimated Noise
from Tire
Installation
Center,
dBA (Leq)
Significance
Threshold,a
dBA (Leq)
Exceed over
Significance
Threshold,
dBA (Leq)
Significant
Impact?
R1 52.6 27.9 60.0 0.0 No
R2 43.7 29.0 60.0 0.0 No
R3 63.8 30.0 60.0 0.0 No
R4 50.9 9.0 60.0 0.0 No
R5 49.4 11.5 60.0 0.0 No
R6 50.0 32.7 65.0 0.0 No
Notes:
a Significance threshold equal to City’s daytime noise limits.

Source: AES, 2025

3.5.8 Composite On-Site Operational Noise Levels
An evaluation of composite operational noise levels, including all Project on-site noise sources plus existing ambient noise levels, was conducted to identify the potential Project-related noise level increase that may occur at the noise-sensitive receptor locations. Noise sources associated with the Project would include mechanical equipment, loading dock operation, warehouse delivery trucks, trash compactors, parking lot operation, and tire center. Table 22 (on page 36) presents the estimated daytime noise levels from Project-related on-site noise sources at the off-site noise receptors. As indicated in Table 22, the estimated daytime composite noise levels 21 City of Redding, River Crossing Marketplace Specific Plan Draft EIR, Section 4.1 Noise, April 2018.

Item: 11
1895
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026
due to the Project would range from 38.6 dBA (Leq) at receptor R1 to 49.8 dBA (Leq) at receptor R3, which would be below the Project daytime significance threshold of 60.0 dBA (Leq) at receptors R1 through R3 and 65.0 dBA (Leq) at receptor R6. Table 23 (on page 36) presents the estimated nighttime noise levels from Project-related on-site noise sources at the off-site noise receptors. As indicated in Table 23, the estimated nighttime composite noise levels due to the Project would range from 36.5 dBA (Leq) at receptor R1 to 49.6 dBA (Leq) at receptor R3, which would be below the Project nighttime significance threshold of 50.0 dBA (Leq) at receptors R1 through R5 and 65 dBA (Leq) at receptor R6. Therefore, the composite noise level impacts due to Project operation would be less than significant.

Item: 11
1896
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026
Table 22. Composite On-Site Operational Noise Impacts – Daytime Hours Receptor
Location
Calculated Project-Related Noise Levels, dBA (Leq) Project Composite
Noise Levels,
dBA (Leq)
Daytime
Ambient
Noise Levels,
dBA (Leq)
Significance
Thresholda
dBA (Leq)
Significant
Mechanical Impact?
Loading
Dock
Delivery
Truck
Trash
Compactor
Parking
Lot
Parking
Lot
Cleaning
Tire
Installation
Center
R1 33.1 15.0 26.0 11.4 33.3 33.1 27.9 38.6 52.6 60.0 No R2 30.9 12.8 35.6 8.7 34.2 34.8 29.0 40.5 43.7 60.0 No R3 31.7 19.6 49.3 11.0 35.2 35.8 30.0 49.8 63.8 60.0 No R4 31.4 36.8 40.9 28.9 36.7 38.2 9.0 44.8 50.9 60.0 No R5 39.4 25.0 30.2 41.6 34.4 43.9 11.5 47.1 49.4 60.0 No R6 38.3 20.8 39.3 16.2 44.5 44.9 32.7 48.8 50.0 65.0 No Notes: a Significance threshold equal to City’s daytime noise limits.

Source: AES, 2026
Table 23. Composite On-Site Operational Noise Impacts – Nighttime Hours Receptor
Location
Calculated Project-Related Noise Levels, dBA (Leq) Project Composite
Noise Levels,
dBA (Leq)
Nighttime
Ambient
Noise Levels,
dBA (Leq)
Significance
Thresholda
dBA (Leq)
Significant
Mechanical Impact?
Loading
Dock
Delivery
Truck
Trash
Compactor
Parking
Lot
Parking
Lot
Cleaning
Tire
Installation
Center
R1 33.1 15.0 26.0 --b --b 33.1 --b 36.5 48.5 50.0 No R2 30.9 12.8 35.6 --b --b 34.8 --b 39.0 41.5 50.0 No R3 31.7 19.6 49.3 --b --b 35.8 --b 49.6 53.7 50.0 No R4 31.4 36.8 40.9 --b --b 38.2 --b 44.0 37.6 50.0 No R5 39.4 25.0 30.2 --b --b 43.9 --b 45.4 44.3 50.0 No R6 38.3 20.8 39.3 --b --b 44.9 --b 46.7 40.0 65.0 No Notes: a Significance threshold equal to City’s nighttime noise limits. b Not operating during the nighttime hours (10:00 p.m. to 7:00 a.m.) Source: AES, 2026
1897
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026

3.5.9 Off-Site Traffic
Traffic volumes at the roadway segments in the vicinity of the Project Site were provided by the Project traffic consultant.22 As presented in the Project traffic analysis, the Project is expected to generate a total of 590 and 1,071 peak hour trips for weekday and weekend, respectively. Therefore, the Project off-site traffic noise analysis is based on weekend, as a conservative analysis. Table 24 (on page 39) provides a summary of the off-site traffic noise analysis for typical weekend. Project-generated traffic noise impacts were evaluated by comparing the increase in noise levels from the “future without project” condition to the “future with project” condition with the Project’s significance threshold. As presented in Table 24, the Project would result in a maximum noise increase of 2.5 dBA CNEL (relative to the “future without project” conditions) along Town Centre Drive (between Alton Parkway and Bake Parkway). The estimated traffic noise levels along Alton Parkway (East of Portola Parkway), Rancho Parkway, Town Center Drive (between Alton Parkway and Bake Parkway), and Portola Parkway (North of Alton Parkway) fall between 60 dBA and 65 dBA CNEL, which would be below the 3 dBA CNEL significance threshold (applicable to noise levels between 60 dBA and 65 dBA CNEL). The noise increase at all other roadway segments is less than 1.2 dBA CNEL, which would be below the 1.5 dBA CNEL significance threshold (applicable to noise levels greater than 65 dBA CNEL).

The analysis of traffic noise impacts described above was based on the incremental increase in traffic noise levels attributable to the Project as compared to “future without project” conditions. An additional analysis was performed to determine the potential noise impacts based on the increase in noise levels due to Project-related traffic (“existing with project” conditions) compared with the existing without traffic noise conditions. As presented in Table 24, traffic from the Project would result in a maximum noise increase of 2.6 dBA CNEL (relative to the “existing without project” conditions) along Towne Centre Drive (between Alton Parkway and Bake Parkway). The estimated traffic noise levels along Alton Parkway (East of Portola Parkway), Rancho Parkway, Town Center Drive (between Alton Parkway and Bake Parkway), and Portola Parkway (North of Alton Parkway) fall between 60 dBA and 65 dBA CNEL, which would be below the 3 dBA CNEL significance threshold. The noise increase at all other roadway segments is less than 1.3 dBA CNEL, which would be below the

1.5 dBA CNEL significance threshold.

The Project combined with the future growth and related projects in the area would produce traffic (i.e., off-site mobile sources) that would generate cumulative traffic roadway noise.

Cumulative noise impacts due to off-site traffic were analyzed by comparing the projected increase in traffic noise levels from “existing conditions” to “future plus Project” conditions to 22 Kittelson & Associates, Inc., Foothill Ranch Costco Focused Transportation Impact Study, September 19, 2025.

Item: 11
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Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026
the applicable significance criteria. As presented in Table 24 (on page 39), cumulative traffic would result in a maximum noise increase of 2.8 dBA CNEL along Towne Centre Drive (between Alton Parkway and Bake Parkway) The estimated traffic noise levels along Alton Parkway (East of Portola Parkway), Rancho Parkway, Town Center Drive (between Alton Parkway and Bake Parkway), and Portola Parkway (North of Alton Parkway) fall between 60 dBA and 65 dBA CNEL, which would be below the 3 dBA CNEL significance threshold. The noise increase at all other roadway segments are 1.4 dBA CNEL or lower, which would be below the 1.5 dBA CNEL significance threshold. Therefore, noise impacts associated with off-site traffic would be less than significant.

Item: 11
1899
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026
Table 24. Off-Site Traffic Noise Impacts
Roadway Segment
Calculated Traffic Noise Levels,
CNEL (dBA) Increase in Noise Levels, CNEL (dBA) Significant Impact? Existing
(A)
Existing
+
Project
(B)
Future
Without
Project
(C)
Future
With
Project
(D)
Project
Level
(vs. Existing)
(B – A)
Project
Level
(vs. Future
w/o Project)
(D – C)
Cumulative
Level
(D – A)
Project
Level
Cumulative
Level
Alton Parkway - West of Rancho Pkwy. 68.1 68.8 68.4 69.0 0.7 0.6 0.9 No No - Between Rancho Pkwy. and Towne Centre Dr. 67.8 68.9 68.1 69.2 1.1 1.1 1.4 No No - Between Towne Centre Dr. & Portola Pkwy. 66.4 66.8 66.7 67.0 0.4 0.3 0.6 No No - East of Portola Pkwy. 63.5 63.8 63.7 64.1 0.3 0.4 0.6 No No Bake Parkway - West of Towne Centre Dr. 66.2 67.4 66.5 67.6 1.2 1.1 1.4 No No - Between Towne Centre Dr. & Portola Pkwy. 67.2 67.4 67.5 67.7 0.2 0.2 0.5 No No - East of Portola Pkwy. 67.1 68.0 67.4 68.3 0.9 0.9 1.2 No No Rancho Parkway - North of Alton Pkwy. 59.3 59.3 59.5 59.5 0.0 0.0 0.2 No No - South of Alton Pkwy. 59.6 60.0 59.9 60.3 0.4 0.4 0.7 No No Towne Centre Drive - Between Alton Pkwy. & Bake Pkwy. 62.0 64.6 62.3 64.8 2.6 2.5 2.8 No NoPortola Parkway - North of Alton Pkwy. 61.1 61.5 61.4 61.8 0.4 0.4 0.7 No No - Between Alton Pkwy. & Bake Pkwy. 66.7 66.7 67.0 67.0 0.0 0.0 0.3 No No - South of Bake Pkwy. 67.8 68.4 68.1 68.7 0.6 0.6 0.9 No No Source: AES, 2025 1900
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc.

January 2026
4 MITIGATION MEASURES

4.1 Construction Noise
As analyzed above, the Project construction activities would not result in significant impacts at the off-site noise sensitive receptors. Therefore, no mitigation measures are required.

4.2 Construction Vibration
As analyzed above, vibration impacts from on-site construction activities would not result in significant impacts. Therefore, no mitigation measures are required.

4.3 Operational Noise
As discussed above, operation of the Project would not result in a significant noise impact during operation. Therefore, no mitigation measures are required.

Item: 11
1901
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc. January 2026
Appendix A
Ambient Noise Measurements

Item: 11
1902
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Location: R1
Date: 7/14/2025
Time Leq
10:03:12 AM 52.4
10:03:22 AM 54.6
10:03:32 AM 59.4
10:03:42 AM 57.3
10:03:52 AM 54.7
10:04:02 AM 56.5
10:04:12 AM 50.3
10:04:22 AM 53.1
10:04:32 AM 51.1
10:04:42 AM 46.5
10:04:52 AM 44.6
10:05:02 AM 46.1
10:05:12 AM 49.2
10:05:22 AM 52.0
10:05:32 AM 55.3
10:05:42 AM 55.7
10:05:52 AM 51.5
10:06:02 AM 56.2
10:06:12 AM 55.4
10:06:22 AM 56.1
10:06:32 AM 54.7
10:06:42 AM 57.5
10:06:52 AM 54.6
10:07:02 AM 54.0
10:07:12 AM 55.2
10:07:22 AM 55.3
10:07:32 AM 56.1
10:07:42 AM 50.4
10:07:52 AM 53.7
10:08:02 AM 53.2
10:08:12 AM 56.1
10:08:22 AM 55.5
10:08:32 AM 53.0
10:08:42 AM 53.9
10:08:52 AM 42.4
10:09:02 AM 52.4
10:09:12 AM 50.9
10:09:22 AM 55.4
10:09:32 AM 58.2
10:09:42 AM 53.4
10:09:52 AM 44.5
10:10:02 AM 55.6
10:10:12 AM 55.0
10:10:22 AM 44.0
10:10:32 AM 47.1
10:10:42 AM 46.9
10/23/2025
Item: 11
1903
A E S
Acoustical Engineering Services
10:10:52 AM 50.7
10:11:02 AM 51.3
10:11:12 AM 45.7
10:11:22 AM 49.2
10:11:32 AM 51.0
10:11:42 AM 50.1
10:11:52 AM 48.2
10:12:02 AM 51.1
10:12:12 AM 48.2
10:12:22 AM 54.5
10:12:32 AM 49.0
10:12:42 AM 50.0
10:12:52 AM 47.3
10:13:02 AM 48.4
10:13:12 AM 50.5
10:13:22 AM 49.6
10:13:32 AM 50.6
10:13:42 AM 48.8
10:13:52 AM 49.9
10:14:02 AM 46.5
10:14:12 AM 44.0
10:14:22 AM 48.7
10:14:32 AM 47.0
10:14:42 AM 41.1
10:14:52 AM 43.8
10:15:02 AM 49.7
10:15:12 AM 50.5
10:15:22 AM 48.8
10:15:32 AM 47.8
10:15:42 AM 42.0
10:15:52 AM 47.5
10:16:02 AM 50.4
10:16:12 AM 55.5
10:16:22 AM 48.0
10:16:32 AM 48.6
10:16:42 AM 43.7
10:16:52 AM 46.2
10:17:02 AM 47.9
10:17:12 AM 55.7
10:17:22 AM 48.7
10:17:32 AM 47.8
10:17:42 AM 55.4
10:17:52 AM 46.6
10:18:02 AM 42.5

52.6 Time Leq
10:01:56 PM 49.3
10:02:06 PM 46.7
10:02:16 PM 41.8
10:02:26 PM 35.7
10/23/2025
Item: 11
1904
A E S
Acoustical Engineering Services
10:02:36 PM 46.1
10:02:46 PM 46.6
10:02:56 PM 44.6
10:03:06 PM 47.5
10:03:16 PM 45.9
10:03:26 PM 45.3
10:03:36 PM 46.5
10:03:46 PM 41.9
10:03:56 PM 35.0
10:04:06 PM 39.9
10:04:16 PM 41.3
10:04:26 PM 49.0
10:04:36 PM 50.3
10:04:46 PM 46.1
10:04:56 PM 43.5
10:05:06 PM 42.6
10:05:16 PM 38.9
10:05:26 PM 43.6
10:05:36 PM 49.0
10:05:46 PM 43.8
10:05:56 PM 46.3
10:06:06 PM 49.1
10:06:16 PM 46.5
10:06:26 PM 43.8
10:06:36 PM 46.0
10:06:46 PM 46.4
10:06:56 PM 51.6
10:07:06 PM 46.3
10:07:16 PM 50.6
10:07:26 PM 48.9
10:07:36 PM 41.5
10:07:46 PM 47.6
10:07:56 PM 45.3
10:08:06 PM 48.7
10:08:16 PM 46.7
10:08:26 PM 48.4
10:08:36 PM 41.2
10:08:46 PM 38.9
10:08:56 PM 49.4
10:09:06 PM 46.8
10:09:16 PM 50.0
10:09:26 PM 44.2
10:09:36 PM 47.6
10:09:46 PM 51.4
10:09:56 PM 50.0
10:10:06 PM 41.3
10:10:16 PM 44.8
10:10:26 PM 46.6
10:10:36 PM 51.5
10:10:46 PM 49.6
10:10:56 PM 41.9
10/23/2025
Item: 11
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A E S
Acoustical Engineering Services
10:11:06 PM 43.4
10:11:16 PM 46.6
10:11:26 PM 44.1
10:11:36 PM 39.3
10:11:46 PM 47.1
10:11:56 PM 45.4
10:12:06 PM 45.4
10:12:16 PM 46.7
10:12:26 PM 45.6
10:12:36 PM 42.1
10:12:46 PM 45.6
10:12:56 PM 47.3
10:13:06 PM 44.2
10:13:16 PM 47.1
10:13:26 PM 46.6
10:13:36 PM 42.6
10:13:46 PM 40.9
10:13:56 PM 45.6
10:14:06 PM 44.9
10:14:16 PM 41.2
10:14:26 PM 39.8
10:14:36 PM 43.2
10:14:46 PM 40.5
10:14:56 PM 56.8
10:15:06 PM 49.6
10:15:16 PM 50.7
10:15:26 PM 46.6
10:15:36 PM 49.0
10:15:46 PM 40.9
10:15:56 PM 42.6
10:16:06 PM 37.5
10:16:16 PM 37.2
10:16:26 PM 62.9
10:16:36 PM 43.9
10:16:46 PM 45.1

48.5 10/23/2025
Item: 11
1906
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Location: R2
Date: 7/14/2025
Time Leq
10:26:35 AM 47.5
10:26:45 AM 48.4
10:26:55 AM 41.8
10:27:05 AM 45.4
10:27:15 AM 43.8
10:27:25 AM 44.1
10:27:35 AM 44.3
10:27:45 AM 44.8
10:27:55 AM 42.8
10:28:05 AM 45.8
10:28:15 AM 43.5
10:28:25 AM 42.6
10:28:35 AM 43.1
10:28:45 AM 42.2
10:28:55 AM 48.4
10:29:05 AM 48.2
10:29:15 AM 46.0
10:29:25 AM 42.9
10:29:35 AM 42.3
10:29:45 AM 41.0
10:29:55 AM 42.6
10:30:05 AM 44.7
10:30:15 AM 45.2
10:30:25 AM 42.6
10:30:35 AM 41.3
10:30:45 AM 41.3
10:30:55 AM 41.6
10:31:05 AM 40.7
10:31:15 AM 42.0
10:31:25 AM 41.8
10:31:35 AM 43.7
10:31:45 AM 42.7
10:31:55 AM 43.3
10:32:05 AM 43.4
10:32:15 AM 41.5
10:32:25 AM 41.1
10:32:35 AM 42.1
10:32:45 AM 42.7
10:32:55 AM 47.4
10:33:05 AM 45.0
10:33:15 AM 49.1
10:33:25 AM 47.0
10:33:35 AM 43.7
10:33:45 AM 40.7
10:33:55 AM 39.7
10:34:05 AM 41.6
10/23/2025
Item: 11
1907
A E S
Acoustical Engineering Services
10:34:15 AM 42.6
10:34:25 AM 43.1
10:34:35 AM 43.1
10:34:45 AM 41.9
10:34:55 AM 43.2
10:35:05 AM 42.0
10:35:15 AM 40.7
10:35:25 AM 39.8
10:35:35 AM 40.1
10:35:45 AM 41.8
10:35:55 AM 42.1
10:36:05 AM 41.6
10:36:15 AM 40.1
10:36:25 AM 41.1
10:36:35 AM 42.6
10:36:45 AM 42.9
10:36:55 AM 41.3
10:37:05 AM 40.4
10:37:15 AM 43.1
10:37:25 AM 41.1
10:37:35 AM 42.3
10:37:45 AM 43.3
10:37:55 AM 45.2
10:38:05 AM 42.5
10:38:15 AM 46.0
10:38:25 AM 45.5
10:38:35 AM 43.4
10:38:45 AM 40.4
10:38:55 AM 40.2
10:39:05 AM 44.1
10:39:15 AM 43.0
10:39:25 AM 43.6
10:39:35 AM 41.4
10:39:45 AM 41.6
10:39:55 AM 42.5
10:40:05 AM 44.0
10:40:15 AM 41.0
10:40:25 AM 41.4
10:40:35 AM 44.9
10:40:45 AM 49.2
10:40:55 AM 42.2
10:41:05 AM 43.7
10:41:15 AM 44.3
10:41:25 AM 41.8

43.7 Time Leq
10:23:43 PM 41.7
10:23:53 PM 40.6
10:24:03 PM 41.4
10:24:13 PM 42.0
10/23/2025
Item: 11
1908
A E S
Acoustical Engineering Services
10:24:23 PM 41.1
10:24:33 PM 41.1
10:24:43 PM 40.6
10:24:53 PM 40.6
10:25:03 PM 43.2
10:25:13 PM 41.6
10:25:23 PM 41.4
10:25:33 PM 43.2
10:25:43 PM 40.8
10:25:53 PM 40.6
10:26:03 PM 42.0
10:26:13 PM 43.2
10:26:23 PM 41.0
10:26:33 PM 39.8
10:26:43 PM 40.4
10:26:53 PM 41.4
10:27:03 PM 40.7
10:27:13 PM 40.7
10:27:23 PM 43.2
10:27:33 PM 41.5
10:27:43 PM 40.6
10:27:53 PM 41.1
10:28:03 PM 41.5
10:28:13 PM 40.9
10:28:23 PM 41.0
10:28:33 PM 41.4
10:28:43 PM 41.2
10:28:53 PM 41.3
10:29:03 PM 41.0
10:29:13 PM 40.3
10:29:23 PM 40.5
10:29:33 PM 40.5
10:29:43 PM 40.3
10:29:53 PM 40.2
10:30:03 PM 40.5
10:30:13 PM 40.5
10:30:23 PM 40.6
10:30:33 PM 40.3
10:30:43 PM 40.9
10:30:53 PM 43.1
10:31:03 PM 41.6
10:31:13 PM 40.9
10:31:23 PM 40.7
10:31:33 PM 40.6
10:31:43 PM 40.9
10:31:53 PM 41.3
10:32:03 PM 41.4
10:32:13 PM 40.6
10:32:23 PM 41.1
10:32:33 PM 41.3
10:32:43 PM 40.6
10/23/2025
Item: 11
1909
A E S
Acoustical Engineering Services
10:32:53 PM 41.3
10:33:03 PM 40.6
10:33:13 PM 40.4
10:33:23 PM 40.6
10:33:33 PM 40.8
10:33:43 PM 41.4
10:33:53 PM 40.6
10:34:03 PM 40.5
10:34:13 PM 41.7
10:34:23 PM 40.4
10:34:33 PM 40.1
10:34:43 PM 40.9
10:34:53 PM 39.9
10:35:03 PM 41.4
10:35:13 PM 43.7
10:35:23 PM 44.9
10:35:33 PM 43.3
10:35:43 PM 42.4
10:35:53 PM 41.6
10:36:03 PM 41.0
10:36:13 PM 41.0
10:36:23 PM 40.3
10:36:33 PM 40.7
10:36:43 PM 40.3
10:36:53 PM 39.9
10:37:03 PM 40.3
10:37:13 PM 40.3
10:37:23 PM 39.6
10:37:33 PM 41.0
10:37:43 PM 41.5
10:37:53 PM 39.9
10:38:03 PM 43.8
10:38:13 PM 41.9
10:38:23 PM 40.8
10:38:33 PM 48.3

41.5 10/23/2025
Item: 11
1910
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Location: R3
Date: 7/14/2025
Time Leq
10:56:43 AM 62.7
10:56:53 AM 57.7
10:57:03 AM 53.3
10:57:13 AM 51.3
10:57:23 AM 57.3
10:57:33 AM 66.3
10:57:43 AM 63.8
10:57:53 AM 60.9
10:58:03 AM 64.0
10:58:13 AM 61.4
10:58:23 AM 56.2
10:58:33 AM 53.6
10:58:43 AM 64.9
10:58:53 AM 68.9
10:59:03 AM 54.2
10:59:13 AM 64.2
10:59:23 AM 66.2
10:59:33 AM 69.9
10:59:43 AM 54.7
10:59:53 AM 51.0
11:00:03 AM 54.9
11:00:13 AM 59.1
11:00:23 AM 56.9
11:00:33 AM 55.5
11:00:43 AM 71.4
11:00:53 AM 70.2
11:01:03 AM 66.4
11:01:13 AM 59.9
11:01:23 AM 70.3
11:01:33 AM 62.6
11:01:43 AM 58.0
11:01:53 AM 64.6
11:02:03 AM 57.4
11:02:13 AM 64.1
11:02:23 AM 65.2
11:02:33 AM 64.6
11:02:43 AM 55.6
11:02:53 AM 51.3
11:03:03 AM 51.6
11:03:13 AM 53.9
11:03:23 AM 59.0
11:03:33 AM 55.9
11:03:43 AM 53.0
11:03:53 AM 60.4
11:04:03 AM 52.1
11:04:13 AM 57.4
10/23/2025
Item: 11
1911
A E S
Acoustical Engineering Services
11:04:23 AM 72.1
11:04:33 AM 58.1
11:04:43 AM 56.1
11:04:53 AM 53.4
11:05:03 AM 53.5
11:05:13 AM 68.0
11:05:23 AM 61.7
11:05:33 AM 55.4
11:05:43 AM 54.5
11:05:53 AM 59.8
11:06:03 AM 56.4
11:06:13 AM 64.4
11:06:23 AM 63.3
11:06:33 AM 57.3
11:06:43 AM 60.0
11:06:53 AM 66.5
11:07:03 AM 72.1
11:07:13 AM 57.7
11:07:23 AM 54.2
11:07:33 AM 51.6
11:07:43 AM 54.2
11:07:53 AM 53.8
11:08:03 AM 56.3
11:08:13 AM 58.2
11:08:23 AM 50.7
11:08:33 AM 65.2
11:08:43 AM 67.2
11:08:53 AM 61.2
11:09:03 AM 52.1
11:09:13 AM 52.0
11:09:23 AM 64.6
11:09:33 AM 64.6
11:09:43 AM 53.9
11:09:53 AM 49.7
11:10:03 AM 54.8
11:10:13 AM 62.5
11:10:23 AM 54.2
11:10:33 AM 60.7
11:10:43 AM 63.5
11:10:53 AM 68.1
11:11:03 AM 71.7
11:11:13 AM 64.1
11:11:23 AM 55.0
11:11:33 AM 66.9

63.8 Time Leq
10:45:34 PM 51.5
10:45:44 PM 44.4
10:45:54 PM 44.8
10:46:04 PM 63.8
10/23/2025
Item: 11
1912
A E S
Acoustical Engineering Services
10:46:14 PM 64.6
10:46:24 PM 49.1
10:46:34 PM 41.9
10:46:44 PM 40.7
10:46:54 PM 40.4
10:47:04 PM 44.7
10:47:14 PM 60.9
10:47:24 PM 51.6
10:47:34 PM 62.1
10:47:44 PM 50.9
10:47:54 PM 43.7
10:48:04 PM 56.6
10:48:14 PM 60.9
10:48:24 PM 63.9
10:48:34 PM 57.5
10:48:44 PM 45.9
10:48:54 PM 62.7
10:49:04 PM 67.4
10:49:14 PM 61.1
10:49:24 PM 63.6
10:49:34 PM 43.3
10:49:44 PM 37.8
10:49:54 PM 39.6
10:50:04 PM 41.9
10:50:14 PM 47.9
10:50:24 PM 59.4
10:50:34 PM 66.0
10:50:44 PM 62.8
10:50:54 PM 48.4
10:51:04 PM 49.2
10:51:14 PM 62.4
10:51:24 PM 47.4
10:51:34 PM 41.3
10:51:44 PM 56.7
10:51:54 PM 51.4
10:52:04 PM 45.2
10:52:14 PM 42.3
10:52:24 PM 43.8
10:52:34 PM 56.9
10:52:44 PM 62.1
10:52:54 PM 53.7
10:53:04 PM 41.6
10:53:14 PM 41.0
10:53:24 PM 42.9
10:53:34 PM 46.3
10:53:44 PM 64.3
10:53:54 PM 56.4
10:54:04 PM 50.7
10:54:14 PM 65.6
10:54:24 PM 60.9
10:54:34 PM 59.9
10/23/2025
Item: 11
1913
A E S
Acoustical Engineering Services
10:54:44 PM 52.7
10:54:54 PM 58.6
10:55:04 PM 69.8
10:55:14 PM 52.3
10:55:24 PM 64.9
10:55:34 PM 58.5
10:55:44 PM 56.8
10:55:54 PM 52.7
10:56:04 PM 57.3
10:56:14 PM 54.9
10:56:24 PM 56.7
10:56:34 PM 52.7
10:56:44 PM 59.7
10:56:54 PM 58.0
10:57:04 PM 55.5
10:57:14 PM 64.3
10:57:24 PM 67.4
10:57:34 PM 57.4
10:57:44 PM 61.5
10:57:54 PM 60.4
10:58:04 PM 49.9
10:58:14 PM 58.9
10:58:24 PM 68.0
10:58:34 PM 55.9
10:58:44 PM 55.0
10:58:54 PM 60.5
10:59:04 PM 47.9
10:59:14 PM 46.9
10:59:24 PM 62.5
10:59:34 PM 61.6
10:59:44 PM 65.5
10:59:54 PM 67.2
11:00:04 PM 48.9
11:00:14 PM 50.6
11:00:24 PM 49.8

53.7 10/23/2025
Item: 11
1914
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Location: R4
Date: 7/14/2025
Time Leq
11:23:39 AM 46.9
11:23:49 AM 48.8
11:23:59 AM 50.7
11:24:09 AM 54.4
11:24:19 AM 60.9
11:24:29 AM 56.4
11:24:39 AM 51.6
11:24:49 AM 49.9
11:24:59 AM 51.9
11:25:09 AM 51.5
11:25:19 AM 49.0
11:25:29 AM 51.3
11:25:39 AM 50.6
11:25:49 AM 51.1
11:25:59 AM 52.8
11:26:09 AM 46.5
11:26:19 AM 47.2
11:26:29 AM 48.4
11:26:39 AM 47.7
11:26:49 AM 51.6
11:26:59 AM 49.5
11:27:09 AM 46.4
11:27:19 AM 47.5
11:27:29 AM 47.8
11:27:39 AM 46.5
11:27:49 AM 47.3
11:27:59 AM 50.1
11:28:09 AM 48.5
11:28:19 AM 47.2
11:28:29 AM 48.5
11:28:39 AM 49.4
11:28:49 AM 49.2
11:28:59 AM 67.6
11:29:09 AM 73.5
11:29:19 AM 74.5
11:29:29 AM 65.6
11:29:39 AM 57.2
11:29:49 AM 68.7
11:29:59 AM 68.7
11:30:09 AM 55.2
11:30:19 AM 54.1
11:30:29 AM 53.0
11:30:39 AM 50.1
11:30:49 AM 48.9
11:30:59 AM 48.1
11:31:09 AM 46.0
10/23/2025
Item: 11
1915
A E S
Acoustical Engineering Services
11:31:19 AM 46.6
11:31:29 AM 50.9
11:31:39 AM 47.4
11:31:49 AM 46.1
11:31:59 AM 47.8
11:32:09 AM 53.9
11:32:19 AM 49.9
11:32:29 AM 48.9
11:32:39 AM 50.9
11:32:49 AM 51.1
11:32:59 AM 51.2
11:33:09 AM 48.7
11:33:19 AM 48.3
11:33:29 AM 48.7
11:33:39 AM 50.6
11:33:49 AM 49.6
11:33:59 AM 50.6
11:34:09 AM 48.7
11:34:19 AM 49.9
11:34:29 AM 46.7
11:34:39 AM 49.6
11:34:49 AM 50.5
11:34:59 AM 50.9
11:35:09 AM 53.7
11:35:19 AM 53.2
11:35:29 AM 51.0
11:35:39 AM 51.2
11:35:49 AM 52.1
11:35:59 AM 48.0
11:36:09 AM 45.6
11:36:19 AM 47.1
11:36:29 AM 50.0
11:36:39 AM 48.1
11:36:49 AM 47.0
11:36:59 AM 48.3
11:37:09 AM 51.0
11:37:19 AM 50.2
11:37:29 AM 48.7
11:37:39 AM 45.3
11:37:49 AM 46.9
11:37:59 AM 47.5
11:38:09 AM 48.3
11:38:19 AM 50.2
11:38:29 AM 50.7

50.9 Time Leq
11:12:36 PM 41.1
11:12:46 PM 34.1
11:12:56 PM 34.8
11:13:06 PM 33.5
10/23/2025
Item: 11
1916
A E S
Acoustical Engineering Services
11:13:16 PM 34.7
11:13:26 PM 33.3
11:13:36 PM 33.2
11:13:46 PM 34.4
11:13:56 PM 35.0
11:14:06 PM 35.5
11:14:16 PM 40.6
11:14:26 PM 43.5
11:14:36 PM 43.7
11:14:46 PM 43.4
11:14:56 PM 42.0
11:15:06 PM 39.5
11:15:16 PM 37.2
11:15:26 PM 36.2
11:15:36 PM 36.9
11:15:46 PM 37.9
11:15:56 PM 38.8
11:16:06 PM 40.6
11:16:16 PM 41.2
11:16:26 PM 41.5
11:16:36 PM 39.1
11:16:46 PM 37.7
11:16:56 PM 37.1
11:17:06 PM 36.3
11:17:16 PM 35.7
11:17:26 PM 34.6
11:17:36 PM 34.3
11:17:46 PM 34.0
11:17:56 PM 35.7
11:18:06 PM 39.9
11:18:16 PM 37.9
11:18:26 PM 34.8
11:18:36 PM 37.5
11:18:46 PM 36.1
11:18:56 PM 35.0
11:19:06 PM 34.8
11:19:16 PM 35.0
11:19:26 PM 33.3
11:19:36 PM 40.3
11:19:46 PM 32.9
11:19:56 PM 32.8
11:20:06 PM 32.9
11:20:16 PM 33.6
11:20:26 PM 34.0
11:20:36 PM 33.5
11:20:46 PM 32.9
11:20:56 PM 32.9
11:21:06 PM 43.4
11:21:16 PM 37.4
11:21:26 PM 36.3
11:21:36 PM 35.2
10/23/2025
Item: 11
1917
A E S
Acoustical Engineering Services
11:21:46 PM 35.0
11:21:56 PM 35.7
11:22:06 PM 36.6
11:22:16 PM 35.9
11:22:26 PM 40.1
11:22:36 PM 34.0
11:22:46 PM 35.6
11:22:56 PM 33.1
11:23:06 PM 35.7
11:23:16 PM 35.8
11:23:26 PM 32.4
11:23:36 PM 33.8
11:23:46 PM 33.1
11:23:56 PM 32.9
11:24:06 PM 32.5
11:24:16 PM 33.1
11:24:26 PM 33.8
11:24:36 PM 33.8
11:24:46 PM 33.0
11:24:56 PM 32.6
11:25:06 PM 33.7
11:25:16 PM 34.5
11:25:26 PM 33.5
11:25:36 PM 33.8
11:25:46 PM 32.7
11:25:56 PM 33.8
11:26:06 PM 38.6
11:26:16 PM 36.9
11:26:26 PM 40.3
11:26:36 PM 42.7
11:26:46 PM 42.4
11:26:56 PM 41.5
11:27:06 PM 40.2
11:27:16 PM 38.8
11:27:26 PM 37.2

37.6 10/23/2025
Item: 11
1918
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Location: R5
Date: 7/14/2025
Time Leq
11:52:07 AM 43.8
11:52:17 AM 42.0
11:52:27 AM 42.5
11:52:37 AM 42.1
11:52:47 AM 43.3
11:52:57 AM 44.5
11:53:07 AM 44.9
11:53:17 AM 46.4
11:53:27 AM 43.0
11:53:37 AM 52.1
11:53:47 AM 45.4
11:53:57 AM 44.3
11:54:07 AM 45.6
11:54:17 AM 47.9
11:54:27 AM 50.3
11:54:37 AM 46.3
11:54:47 AM 44.7
11:54:57 AM 51.5
11:55:07 AM 46.0
11:55:17 AM 44.2
11:55:27 AM 47.8
11:55:37 AM 49.6
11:55:47 AM 51.0
11:55:57 AM 47.8
11:56:07 AM 47.2
11:56:17 AM 47.8
11:56:27 AM 50.6
11:56:37 AM 59.1
11:56:47 AM 60.2
11:56:57 AM 57.1
11:57:07 AM 46.3
11:57:17 AM 44.6
11:57:27 AM 44.8
11:57:37 AM 43.8
11:57:47 AM 41.2
11:57:57 AM 41.6
11:58:07 AM 45.3
11:58:17 AM 44.3
11:58:27 AM 45.2
11:58:37 AM 46.5
11:58:47 AM 45.0
11:58:57 AM 46.5
11:59:07 AM 58.6
11:59:17 AM 49.6
11:59:27 AM 44.8
11:59:37 AM 45.0
10/23/2025
Item: 11
1919
A E S
Acoustical Engineering Services
11:59:47 AM 42.8
11:59:57 AM 46.9
12:00:07 PM 49.6
12:00:17 PM 53.3
12:00:27 PM 47.7
12:00:37 PM 45.0
12:00:47 PM 45.2
12:00:57 PM 45.0
12:01:07 PM 42.8
12:01:17 PM 42.5
12:01:27 PM 42.4
12:01:37 PM 43.8
12:01:47 PM 47.0
12:01:57 PM 50.6
12:02:07 PM 47.2
12:02:17 PM 45.4
12:02:27 PM 46.4
12:02:37 PM 44.3
12:02:47 PM 43.8
12:02:57 PM 46.0
12:03:07 PM 49.8
12:03:17 PM 46.1
12:03:27 PM 49.9
12:03:37 PM 46.2
12:03:47 PM 45.7
12:03:57 PM 46.2
12:04:07 PM 48.6
12:04:17 PM 47.9
12:04:27 PM 43.8
12:04:37 PM 42.3
12:04:47 PM 43.7
12:04:57 PM 46.0
12:05:07 PM 45.1
12:05:17 PM 46.1
12:05:27 PM 43.1
12:05:37 PM 45.2
12:05:47 PM 49.9
12:05:57 PM 49.3
12:06:07 PM 47.4
12:06:17 PM 57.6
12:06:27 PM 47.1
12:06:37 PM 46.7
12:06:47 PM 45.6
12:06:57 PM 46.1

49.4 Time Leq
11:41:37 PM 45.7
11:41:47 PM 41.9
11:41:57 PM 37.9
11:42:07 PM 36.9
10/23/2025
Item: 11
1920
A E S
Acoustical Engineering Services
11:42:17 PM 42.4
11:42:27 PM 46.1
11:42:37 PM 37.6
11:42:47 PM 37.3
11:42:57 PM 38.7
11:43:07 PM 41.9
11:43:17 PM 46.9
11:43:27 PM 47.6
11:43:37 PM 47.0
11:43:47 PM 47.1
11:43:57 PM 47.1
11:44:07 PM 43.6
11:44:17 PM 41.6
11:44:27 PM 43.2
11:44:37 PM 44.3
11:44:47 PM 40.8
11:44:57 PM 40.6
11:45:07 PM 41.7
11:45:17 PM 40.9
11:45:27 PM 49.8
11:45:37 PM 45.4
11:45:47 PM 41.9
11:45:57 PM 40.5
11:46:07 PM 45.5
11:46:17 PM 42.9
11:46:27 PM 42.2
11:46:37 PM 43.4
11:46:47 PM 47.5
11:46:57 PM 45.1
11:47:07 PM 45.7
11:47:17 PM 41.7
11:47:27 PM 41.6
11:47:37 PM 43.9
11:47:47 PM 48.9
11:47:57 PM 43.0
11:48:07 PM 41.9
11:48:17 PM 41.4
11:48:27 PM 45.4
11:48:37 PM 42.8
11:48:47 PM 44.7
11:48:57 PM 45.9
11:49:07 PM 46.4
11:49:17 PM 42.5
11:49:27 PM 42.8
11:49:37 PM 41.6
11:49:47 PM 40.9
11:49:57 PM 41.3
11:50:07 PM 43.1
11:50:17 PM 45.8
11:50:27 PM 45.5
11:50:37 PM 47.3
10/23/2025
Item: 11
1921
A E S
Acoustical Engineering Services
11:50:47 PM 44.7
11:50:57 PM 44.6
11:51:07 PM 42.1
11:51:17 PM 41.8
11:51:27 PM 41.6
11:51:37 PM 43.3
11:51:47 PM 42.2
11:51:57 PM 42.3
11:52:07 PM 42.1
11:52:17 PM 42.8
11:52:27 PM 45.9
11:52:37 PM 47.8
11:52:47 PM 47.4
11:52:57 PM 47.3
11:53:07 PM 46.1
11:53:17 PM 43.4
11:53:27 PM 45.9
11:53:37 PM 43.1
11:53:47 PM 41.9
11:53:57 PM 44.7
11:54:07 PM 47.4
11:54:17 PM 44.5
11:54:27 PM 42.9
11:54:37 PM 40.9
11:54:47 PM 42.8
11:54:57 PM 44.5
11:55:07 PM 44.7
11:55:17 PM 42.0
11:55:27 PM 42.2
11:55:37 PM 42.9
11:55:47 PM 42.0
11:55:57 PM 42.9
11:56:07 PM 43.2
11:56:17 PM 42.4
11:56:27 PM 45.4

44.3 10/23/2025
Item: 11
1922
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc. January 2026
Appendix B
Construction Noise & Vibration Calculations Worksheets

Item: 11
1923
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Demolition
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Concrete/Industrial Saws 1 90 20% 1800 0
Excavator 1 81 40% 1800 0
Rubber Tired Dozers 1 82 40% 1825 0
Excavator 1 81 40% 1825 0
Rubber Tired Dozers 1 82 40% 1850 0
Excavator 1 81 40% 1850 0
6 Receptor: R1
Results:
1-hour Leq: 55.6
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1924
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Site Prep
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Rubber Tired Dozers 1 82 40% 1285 0
Tractors/Loaders/Backhoes 1 84 40% 1285 0
Rubber Tired Dozers 1 82 40% 1310 0
Tractors/Loaders/Backhoes 1 84 40% 1310 0
Rubber Tired Dozers 1 82 40% 1335 0
Tractors/Loaders/Backhoes 1 84 40% 1335 0
Tractors/Loaders/Backhoes 1 84 40% 1360 0
7 Receptor: R1
Results:
1-hour Leq: 59.3
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1925
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Grading
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Excavator 1 81 40% 1285 0
Grader 1 85 40% 1285 0
Rubber Tired Dozers 1 82 40% 1310 0
Scrapers 1 85 40% 1310 0
Tractors/Loaders/Backhoes 1 84 40% 1335 0
Excavator 1 81 40% 1335 0
Scrapers 1 85 40% 1360 0
Tractors/Loaders/Backhoes 1 84 40% 1360 0
8 Receptor: R1
Results:
1-hour Leq: 60.3
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1926
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Building Construction
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Cranes (Mobile) 1 81 16% 1570 0
Forklift 1 75 20% 1570 0
Generator Set 1 82 50% 1595 0
Tractors/Loaders/Backhoes 1 84 40% 1595 0
Welders 1 74 40% 1620 0
Forklift 1 75 20% 1620 0
Forklift 1 75 20% 1645 0
Tractors/Loaders/Backhoes 1 84 40% 1645 0
Tractors/Loaders/Backhoes 1 84 40% 1670 0
9 Receptor: R1
Results:
1-hour Leq: 56.1
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1927
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Paving
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Pavers 1 77 50% 1285 0
Paving Equipment 1 77 50% 1285 0
Rollers 1 80 20% 1310 0
Pavers 1 77 50% 1310 0
Paving Equipment 1 77 50% 1335 0
Rollers 1 80 20% 1335 0
6 Receptor: R1
Results:
1-hour Leq: 53.1
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1928
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Architectural Coating
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Air Compressors 1 78 40% 1570 0
1 Receptor: R1
Results:
1-hour Leq: 44.1
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1929
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Demolition
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Concrete/Industrial Saws 1 90 20% 2165 0
Excavator 1 81 40% 2165 0
Rubber Tired Dozers 1 82 40% 2190 0
Excavator 1 81 40% 2190 0
Rubber Tired Dozers 1 82 40% 2215 0
Excavator 1 81 40% 2215 0
6 Receptor: R2
Results:
1-hour Leq: 54.0
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1930
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Site Prep
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Rubber Tired Dozers 1 82 40% 1450 0
Tractors/Loaders/Backhoes 1 84 40% 1450 0
Rubber Tired Dozers 1 82 40% 1475 0
Tractors/Loaders/Backhoes 1 84 40% 1475 0
Rubber Tired Dozers 1 82 40% 1500 0
Tractors/Loaders/Backhoes 1 84 40% 1500 0
Tractors/Loaders/Backhoes 1 84 40% 1525 0
7 Receptor: R2
Results:
1-hour Leq: 58.3
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1931
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Grading
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Excavator 1 81 40% 1450 0
Grader 1 85 40% 1450 0
Rubber Tired Dozers 1 82 40% 1475 0
Scrapers 1 85 40% 1475 0
Tractors/Loaders/Backhoes 1 84 40% 1500 0
Excavator 1 81 40% 1500 0
Scrapers 1 85 40% 1525 0
Tractors/Loaders/Backhoes 1 84 40% 1525 0
8 Receptor: R2
Results:
1-hour Leq: 59.2
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1932
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Building Construction
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Cranes (Mobile) 1 81 16% 1910 0
Forklift 1 75 20% 1910 0
Generator Set 1 82 50% 1935 0
Tractors/Loaders/Backhoes 1 84 40% 1935 0
Welders 1 74 40% 1960 0
Forklift 1 75 20% 1960 0
Forklift 1 75 20% 1985 0
Tractors/Loaders/Backhoes 1 84 40% 1985 0
Tractors/Loaders/Backhoes 1 84 40% 2010 0
9 Receptor: R2
Results:
1-hour Leq: 54.5
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1933
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Paving
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Pavers 1 77 50% 1450 0
Paving Equipment 1 77 50% 1450 0
Rollers 1 80 20% 1475 0
Pavers 1 77 50% 1475 0
Paving Equipment 1 77 50% 1500 0
Rollers 1 80 20% 1500 0
6 Receptor: R2
Results:
1-hour Leq: 52.1
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1934
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Architectural Coating
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Air Compressors 1 78 40% 1910 0
1 Receptor: R2
Results:
1-hour Leq: 42.4
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1935
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Demolition
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Concrete/Industrial Saws 1 90 20% 1555 5
Excavator 1 81 40% 1555 5
Rubber Tired Dozers 1 82 40% 1580 5
Excavator 1 81 40% 1580 5
Rubber Tired Dozers 1 82 40% 1605 5
Excavator 1 81 40% 1605 5
6 Receptor: R3
Results:
1-hour Leq: 51.8
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1936
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Site Prep
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Rubber Tired Dozers 1 82 40% 1135 5
Tractors/Loaders/Backhoes 1 84 40% 1135 5
Rubber Tired Dozers 1 82 40% 1160 5
Tractors/Loaders/Backhoes 1 84 40% 1160 5
Rubber Tired Dozers 1 82 40% 1185 5
Tractors/Loaders/Backhoes 1 84 40% 1185 5
Tractors/Loaders/Backhoes 1 84 40% 1210 5
7 Receptor: R3
Results:
1-hour Leq: 55.4
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1937
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Grading
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Excavator 1 81 40% 1135 5
Grader 1 85 40% 1135 5
Rubber Tired Dozers 1 82 40% 1160 5
Scrapers 1 85 40% 1160 5
Tractors/Loaders/Backhoes 1 84 40% 1185 5
Excavator 1 81 40% 1185 5
Scrapers 1 85 40% 1210 5
Tractors/Loaders/Backhoes 1 84 40% 1210 5
8 Receptor: R3
Results:
1-hour Leq: 56.3
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1938
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Building Construction
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Cranes (Mobile) 1 81 16% 1610 5
Forklift 1 75 20% 1610 5
Generator Set 1 82 50% 1635 5
Tractors/Loaders/Backhoes 1 84 40% 1635 5
Welders 1 74 40% 1660 5
Forklift 1 75 20% 1660 5
Forklift 1 75 20% 1685 5
Tractors/Loaders/Backhoes 1 84 40% 1685 5
Tractors/Loaders/Backhoes 1 84 40% 1710 5
9 Receptor: R3
Results:
1-hour Leq: 50.9
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1939
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Paving
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Pavers 1 77 50% 1135 5
Paving Equipment 1 77 50% 1135 5
Rollers 1 80 20% 1160 5
Pavers 1 77 50% 1160 5
Paving Equipment 1 77 50% 1185 5
Rollers 1 80 20% 1185 5
6 Receptor: R3
Results:
1-hour Leq: 49.2
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1940
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Architectural Coating
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Air Compressors 1 78 40% 1610 5
1 Receptor: R3
Results:
1-hour Leq: 38.9
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1941
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Demolition
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Concrete/Industrial Saws 1 90 20% 1765 5
Excavator 1 81 40% 1765 5
Rubber Tired Dozers 1 82 40% 1790 5
Excavator 1 81 40% 1790 5
Rubber Tired Dozers 1 82 40% 1815 5
Excavator 1 81 40% 1815 5
6 Receptor: R4
Results:
1-hour Leq: 50.8
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1942
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Site Prep
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Rubber Tired Dozers 1 82 40% 1720 5
Tractors/Loaders/Backhoes 1 84 40% 1720 5
Rubber Tired Dozers 1 82 40% 1745 5
Tractors/Loaders/Backhoes 1 84 40% 1745 5
Rubber Tired Dozers 1 82 40% 1770 5
Tractors/Loaders/Backhoes 1 84 40% 1770 5
Tractors/Loaders/Backhoes 1 84 40% 1795 5
7 Receptor: R4
Results:
1-hour Leq: 51.8
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1943
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Grading
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Excavator 1 81 40% 1720 5
Grader 1 85 40% 1720 5
Rubber Tired Dozers 1 82 40% 1745 5
Scrapers 1 85 40% 1745 5
Tractors/Loaders/Backhoes 1 84 40% 1770 5
Excavator 1 81 40% 1770 5
Scrapers 1 85 40% 1795 5
Tractors/Loaders/Backhoes 1 84 40% 1795 5
8 Receptor: R4
Results:
1-hour Leq: 52.8
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1944
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Building Construction
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Cranes (Mobile) 1 81 16% 2015 5
Forklift 1 75 20% 2015 5
Generator Set 1 82 50% 2040 5
Tractors/Loaders/Backhoes 1 84 40% 2040 5
Welders 1 74 40% 2065 5
Forklift 1 75 20% 2065 5
Forklift 1 75 20% 2090 5
Tractors/Loaders/Backhoes 1 84 40% 2090 5
Tractors/Loaders/Backhoes 1 84 40% 2115 5
9 Receptor: R4
Results:
1-hour Leq: 49.0
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1945
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Paving
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Pavers 1 77 50% 1720 5
Paving Equipment 1 77 50% 1720 5
Rollers 1 80 20% 1745 5
Pavers 1 77 50% 1745 5
Paving Equipment 1 77 50% 1770 5
Rollers 1 80 20% 1770 5
6 Receptor: R4
Results:
1-hour Leq: 45.6
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1946
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Architectural Coating
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Air Compressors 1 78 40% 2015 5
1 Receptor: R4
Results:
1-hour Leq: 36.9
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1947
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Demolition
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Concrete/Industrial Saws 1 90 20% 750 0
Excavator 1 81 40% 750 0
Rubber Tired Dozers 1 82 40% 775 0
Excavator 1 81 40% 775 0
Rubber Tired Dozers 1 82 40% 800 0
Excavator 1 81 40% 800 0
6 Receptor: R5
Results:
1-hour Leq: 63.1
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1948
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Site Prep
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Rubber Tired Dozers 1 82 40% 555 0
Tractors/Loaders/Backhoes 1 84 40% 555 0
Rubber Tired Dozers 1 82 40% 580 0
Tractors/Loaders/Backhoes 1 84 40% 580 0
Rubber Tired Dozers 1 82 40% 605 0
Tractors/Loaders/Backhoes 1 84 40% 605 0
Tractors/Loaders/Backhoes 1 84 40% 630 0
7 Receptor: R5
Results:
1-hour Leq: 66.3
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1949
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Grading
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Excavator 1 81 40% 555 0
Grader 1 85 40% 555 0
Rubber Tired Dozers 1 82 40% 580 0
Scrapers 1 85 40% 580 0
Tractors/Loaders/Backhoes 1 84 40% 605 0
Excavator 1 81 40% 605 0
Scrapers 1 85 40% 630 0
Tractors/Loaders/Backhoes 1 84 40% 630 0
8 Receptor: R5
Results:
1-hour Leq: 67.2
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1950
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Building Construction
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Cranes (Mobile) 1 81 16% 665 0
Forklift 1 75 20% 665 0
Generator Set 1 82 50% 690 0
Tractors/Loaders/Backhoes 1 84 40% 690 0
Welders 1 74 40% 715 0
Forklift 1 75 20% 715 0
Forklift 1 75 20% 740 0
Tractors/Loaders/Backhoes 1 84 40% 740 0
Tractors/Loaders/Backhoes 1 84 40% 765 0
9 Receptor: R5
Results:
1-hour Leq: 63.2
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1951
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Paving
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Pavers 1 77 50% 555 0
Paving Equipment 1 77 50% 555 0
Rollers 1 80 20% 580 0
Pavers 1 77 50% 580 0
Paving Equipment 1 77 50% 605 0
Rollers 1 80 20% 605 0
6 Receptor: R5
Results:
1-hour Leq: 60.2
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1952
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Architectural Coating
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Air Compressors 1 78 40% 665 0
1 Receptor: R5
Results:
1-hour Leq: 51.5
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1953
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Demolition
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Concrete/Industrial Saws 1 90 20% 1010 0
Excavator 1 81 40% 1010 0
Rubber Tired Dozers 1 82 40% 1030 0
Excavator 1 81 40% 1030 0
Rubber Tired Dozers 1 82 40% 1050 0
Excavator 1 81 40% 1050 0
6 Receptor: R6
Results:
1-hour Leq: 60.6
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1954
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Site Prep
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Rubber Tired Dozers 1 82 40% 445 0
Tractors/Loaders/Backhoes 1 84 40% 445 0
Rubber Tired Dozers 1 82 40% 465 0
Tractors/Loaders/Backhoes 1 84 40% 465 0
Rubber Tired Dozers 1 82 40% 485 0
Tractors/Loaders/Backhoes 1 84 40% 485 0
Tractors/Loaders/Backhoes 1 84 40% 505 0
7 Receptor: R6
Results:
1-hour Leq: 68.3
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1955
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Grading
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Excavator 1 81 40% 445 0
Grader 1 85 40% 470 0
Rubber Tired Dozers 1 82 40% 470 0
Scrapers 1 85 40% 495 0
Tractors/Loaders/Backhoes 1 84 40% 495 0
Excavator 1 81 40% 520 0
Scrapers 1 85 40% 520 0
Tractors/Loaders/Backhoes 1 84 40% 545 0
8 Receptor: R6
Results:
1-hour Leq: 68.8
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1956
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Building Construction
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Cranes (Mobile) 1 81 16% 760 0
Forklift 1 75 20% 785 0
Generator Set 1 82 50% 785 0
Tractors/Loaders/Backhoes 1 84 40% 810 0
Welders 1 74 40% 810 0
Forklift 1 75 20% 835 0
Forklift 1 75 20% 835 0
Tractors/Loaders/Backhoes 1 84 40% 860 0
Tractors/Loaders/Backhoes 1 84 40% 860 0
9 Receptor: R6
Results:
1-hour Leq: 62.0
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1957
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Paving
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Pavers 1 77 50% 445 0
Paving Equipment 1 77 50% 470 0
Rollers 1 80 20% 470 0
Pavers 1 77 50% 495 0
Paving Equipment 1 77 50% 495 0
Rollers 1 80 20% 520 0
6 Receptor: R6
Results:
1-hour Leq: 61.8
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1958
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Phase: Architectural Coating
Equipment
Description
No. of
Equip.

Reference
Noise Level at
50ft, Lmax
Acoustical
Usage Factor
Distance to
Receptor, ft
Estimated
Noise
Shielding, dBA
Air Compressors 1 78 40% 760 0
1 Receptor: R6
Results:
1-hour Leq: 50.4
Source for Ref. Noise Levels: FHWA RCNM, 2006
10/8/2025
Item: 11
1959
A E S
Acoustical Engineering Services
Project: Costco Foothill Ranch Project
Construction Vibration Impacts
Reference Levels at 25 feet are based on FTA, 2006 (Transit Noise and Vibration Impact Assessment) Calculations using FTA procedure with n= 1.5 (for receptors 25 feet or greater) n= 1.1 (for receptors less than 25 feet, per Caltrans procedure) Table 1: Construction Equipment Vibration Levels (PPV) - Building Damage Distance Level Distance Level Distance Level Distance Level Vibratory Roller 0.210 90 0.031 60 0.057 15 0.368 475 0.003 Large Bulldozer 0.089 90 0.013 60 0.024 15 0.156 475 0.001 Loaded Trucks 0.076 90 0.011 60 0.020 15 0.133 475 0.001 Jackhammer 0.035 90 0.005 60 0.0094 15 0.061 475 0.000
Small bulldozer 0.003 90 0.000 60 0.001 15 0.0053 475 0.000 Table 2a: Construction Equipment Vibration Levels (VdB) - Human Annoyance Distance Level Distance Level Distance Level Distance Level Vibratory Roller 94 1570 40 1910 38 1610 40 2015 37
Large Bulldozer 87 1570 33 1910 31 1610 33 2015 30
Loaded Trucks 86 1570 32 1910 30 1610 32 2015 29
Jackhammer 79 1570 25 1910 23 1610 25 2015 22
Small bulldozer 58 1570 4 1910 2 1610 4 2015 1
Table 2b: Construction Equipment Vibration Levels (VdB) - Human Annoyance Distance Level Distance Level Distance Level Distance Level Vibratory Roller 94 665 51 760 50
Large Bulldozer 87 665 44 760 43
Loaded Trucks 86 665 43 760 42
Jackhammer 79 665 36 760 35
Small bulldozer 58 665 15 760 14
Equipment
Reference
Vibration
Levels at 25
ft., VdB
Estimated Vibration Levels at Off-Site Receptors (at note distance in feet), VdB R5 R6

ON-SITE CONSTRUCTION ACTIVITIES
Equipment
Reference
Vibration
Levels at 25
ft., PPV
Estimated Vibration Levels at nearest off-site building structures, distance in feet, PPV Commercial Buildings to
the North
Commercial Buildings to the
East
Commercial Buildings to
the South
Commercial Buildings to
the West
Equipment
Reference
Vibration
Levels at 25
ft., VdB
Estimated Vibration Levels at Off-Site Receptors (at note distance in feet), VdB R1 R2 R3 R4
Date Printed: 10/8/2025
Item: 11
1960
Costco Wholesale Costco Wholesale Warehouse Project
Foothill Ranch, California
Environmental Noise Impact Study
Acoustical Engineering Services, Inc. January 2026
Appendix C
Operation Noise Calculations Worksheets
Item: 11
1961
A E S
Acoustical Engineering Services
Project Composite Noise Calculations (Leq)
Project: Costco Foothill Ranch Project

DAYTIME HOURS
Receptor Ambient Mechanical Loading Delivery Truck
Trash
Compactors Parking
Parking
Sweeper Tire Center
Project
Composite
Ambient +
Project Increase Threshold
R1 52.6 33.1 15.0 26.0 11.4 33.3 33.1 27.9 38.6 52.8 0.0 60.0 R2 43.7 30.9 12.8 35.6 8.7 34.2 34.8 29.0 40.5 45.4 0.0 60.0 R3 63.8 31.7 19.6 49.3 11.0 35.2 35.8 30.0 49.8 64.0 0.0 60.0 R4 50.9 31.4 36.8 40.9 28.9 36.7 38.2 9.0 44.8 51.9 0.0 60.0 R5 49.4 39.4 25.0 30.2 41.6 34.4 43.9 11.5 47.1 51.4 0.0 60.0 R6 50.0 38.3 20.8 39.3 16.2 44.5 44.9 32.7 48.8 52.5 0.0 65.0

NIGHTTIME HOURS
Receptor Ambient Mechanical Loading Delivery Truck
Trash
Compactors Parking
Parking
Sweeper Tire Center
Project
Composite
Ambient +
Project Increase Threshold
R1 48.5 33.1 15.0 26.0 33.1 36.5 48.8 0.0 50.0
R2 41.5 30.9 12.8 35.6 34.8 39.0 43.4 0.0 50.0
R3 53.7 31.7 19.6 49.3 35.8 49.6 55.1 0.0 50.0
R4 37.6 31.4 36.8 40.9 38.2 44.0 44.9 0.0 50.0
R5 44.3 39.4 25.0 30.2 43.9 45.4 47.9 0.0 50.0
R6 40.0 38.3 20.8 39.3 44.9 46.7 47.5 0.0 65.0
1/22/2026
Item: 11
1962
A E S
Acoustical Engineering Services
Mechanical Noise Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels,
dBA (Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 33.1 48.5 48.6 50.0
R2 30.9 41.5 41.9 50.0
R3 31.7 53.7 53.7 50.0
R4 31.4 37.6 38.5 50.0
R5 39.4 44.3 45.5 50.0
R6 38.3 40.0 42.2 65.0
Assumptions:

Carrier Roof Top Units: 84 dBA Lw
Rooftop Condenser Unit: 98 dBA Lw
Generator: 90 dBA Lw
1/22/2026
Item: 11
1963
A E S
Acoustical Engineering Services
Loading Dock Noise Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels,
dBA (Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 15.0 48.5 48.5 50.0
R2 12.8 41.5 41.5 50.0
R3 19.6 53.7 53.7 50.0
R4 36.8 37.6 40.2 50.0
R5 25.0 44.3 44.4 50.0
R6 20.8 40.0 40.1 65.0
Assumptions:

SPL Ref. Dist Lw
Loading 70.7 50 102.4
1/22/2026
Item: 11
1964
A E S
Acoustical Engineering Services
Trash Compactors Noise Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels, dBA
(Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 11.4 52.6 52.6 60.0
R2 8.7 43.7 43.7 60.0
R3 11.0 63.8 63.8 60.0
R4 28.9 50.9 50.9 60.0
R5 41.6 49.4 50.1 60.0
R6 16.2 50.0 50.0 65.0
Assumptions:

SPL Ref. Dist Lw
Trash
Compactor
66 50 97.7
1/22/2026
Item: 11
1965
A E S
Acoustical Engineering Services
Tire Installation Center Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels, dBA
(Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 27.9 52.6 52.6 60.0
R2 29.0 43.7 43.8 60.0
R3 30.0 63.8 63.8 60.0
R4 9.0 50.9 50.9 60.0
R5 11.5 49.4 49.4 60.0
R6 32.7 50.0 50.1 65.0
Assumptions:

SPL Ref. Dist Lw
Tire Center 65 50 96.7
1/22/2026
Item: 11
1966
A E S
Acoustical Engineering Services
Parking Lot Noise Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels, dBA
(Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 33.3 52.6 52.7 60.0
R2 34.2 43.7 44.2 60.0
R3 35.2 63.8 63.8 60.0
R4 36.7 50.9 51.1 60.0
R5 34.4 49.4 49.5 60.0
R6 44.5 50.0 51.1 65.0
Assumptions:

Parking Lot # of Spaces
Parking Lot A 50
Parking Lot B 219
Parking Lot C 644
Item: 11
1967
A E S
Acoustical Engineering Services
Parking Lot Sweeper Noise Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels, dBA
(Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 33.1 48.5 48.6 50.0
R2 34.8 41.5 42.3 50.0
R3 35.8 53.7 53.8 50.0
R4 38.2 37.6 40.9 50.0
R5 43.9 44.3 47.1 50.0
R6 44.9 40.0 46.1 65.0
Assumptions:

SPL Ref. Dist Lw
Tire Center 72 50 103.7
Item: 11
1968
A E S
Acoustical Engineering Services
Warehouse Delivery Truck Noise Calculations
Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels (from
SoundPlan),
dBA (Leq)
Ambient Noise
Levels,
dBA (Leq)
Ambient +
Project,
dBA (Leq)
Project Limit,
dBA (Leq)
R1 26.0 48.5 48.5 50.0
R2 35.6 41.5 42.5 50.0
R3 49.3 53.7 55.0 50.0
R4 40.9 37.6 42.6 50.0
R5 30.2 44.3 44.5 50.0
R6 39.3 40.0 42.7 65.0
1/22/2026
Item: 11
1969
A E S
Acoustical Engineering Services
Warehouse Delivery Trucks Noise Calculations - SEL Analysis Project: Costco Foothill Ranch Project
Receptor
Estimated Noise
Levels, Hourly Leq
(One Truck Passby)
from SOUNDPLAN
Calculated SEL at
the Exterior (One
Truck Passby), dBA
SEL Limit for Sleep
Disturbance (At the
Exterior), dBA
Calculated SEL at
the Interior (One
Truck Passby), dBA
SEL Limit for Sleep
Disturbance (At the
Interior), dBA
R1 23.0 58.6 94 45.6 81
R2 32.6 68.2 94 55.2 81
R3 46.3 81.9 94 68.9 81
R4 37.9 73.5 94 60.5 81
R5 27.2 62.8 94 49.8 81
R6 36.3 71.9 94 58.9 81
1/22/2026
Item: 11
1970
Costco Foothill Ranch
Source Levels in dB(A) - 01 Mechanical
Name Source type Lw
dB(A)
Emergency Generator Point 90.0
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical Point 84.3
Mechanical (Condenser) Point 98.0
Mechanical (Condenser) Point 98.0
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1971
Costco Foothill Ranch
Mean propagation Leq - 01 Mechanical
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Receiver R1 Leq,d 33.1 dB(A)
Emergency Generator Point 90.0 0.0 0.0 3 563.02 -66.0 -4.5 -0.4 -1.5 0.0 0.0 20.6 0.0 0.0 0.0 20.6 Mechanical Point 84.3 0.0 0.0 3 575.01 -66.2 -4.5 -0.4 -1.6 0.0 0.0 14.7 0.0 0.0 0.0 14.7 Mechanical Point 84.3 0.0 0.0 3 596.60 -66.5 -4.5 -0.4 -1.6 0.0 0.0 14.3 0.0 0.0 0.0 14.3 Mechanical Point 84.3 0.0 0.0 3 587.07 -66.4 -4.5 -0.4 -1.6 0.0 0.0 14.5 0.0 0.0 0.0 14.5 Mechanical Point 84.3 0.0 0.0 3 601.15 -66.6 -4.5 -0.4 -1.6 0.0 0.0 14.2 0.0 0.0 0.0 14.2 Mechanical Point 84.3 0.0 0.0 3 487.16 -64.7 -4.4 -0.4 -1.3 0.0 0.0 16.4 0.0 0.0 0.0 16.4 Mechanical Point 84.3 0.0 0.0 3 568.16 -66.1 -4.5 -0.4 -1.6 0.0 0.0 14.8 0.0 0.0 0.0 14.8 Mechanical Point 84.3 0.0 0.0 3 540.34 -65.6 -4.4 -0.4 -1.5 0.0 0.0 15.3 0.0 0.0 0.0 15.3 Mechanical Point 84.3 0.0 0.0 3 551.57 -65.8 -4.5 -0.4 -1.5 0.0 0.0 15.2 0.0 0.0 0.0 15.2 Mechanical Point 84.3 0.0 0.0 3 564.83 -66.0 -4.5 -0.4 -1.5 0.0 0.0 14.9 0.0 0.0 0.0 14.9 Mechanical Point 84.3 0.0 0.0 3 549.97 -65.8 -4.4 -0.4 -1.5 0.0 0.0 15.1 0.0 0.0 0.0 15.1 Mechanical Point 84.3 0.0 0.0 3 534.07 -65.5 -4.4 -0.4 -1.5 0.0 0.0 15.5 0.0 0.0 0.0 15.5 Mechanical Point 84.3 0.0 0.0 3 511.21 -65.2 -4.4 -0.4 -1.4 0.0 0.0 15.9 0.0 0.0 0.0 15.9 Mechanical Point 84.3 0.0 0.0 3 518.98 -65.3 -4.4 -0.4 -1.4 0.0 0.0 15.8 0.0 0.0 0.0 15.8 Mechanical Point 84.3 0.0 0.0 3 522.03 -65.3 -4.4 -0.4 -1.4 0.0 0.0 15.7 0.0 0.0 0.0 15.7 Mechanical Point 84.3 0.0 0.0 3 544.04 -65.7 -4.4 -0.4 -1.5 0.0 0.0 15.3 0.0 0.0 0.0 15.3 Mechanical Point 84.3 0.0 0.0 3 553.60 -65.9 -4.5 -0.4 -1.5 0.0 0.0 15.1 0.0 0.0 0.0 15.1 Mechanical Point 84.3 0.0 0.0 3 586.32 -66.4 -4.5 -0.4 -1.6 0.0 0.0 14.5 0.0 0.0 0.0 14.5 Mechanical (Condenser) Point 98.0 0.0 0.0 3 574.75 -66.2 -4.5 -0.4 -1.6 0.0 0.0 28.4 0.0 0.0 0.0 28.4 Mechanical (Condenser) Point 98.0 0.0 0.0 3 585.55 -66.3 -4.5 -0.4 -1.6 0.0 0.0 28.2 0.0 0.0 0.0 28.2 Receiver R2 Leq,d 30.9 dB(A)
Emergency Generator Point 90.0 0.0 0.0 3 713.90 -68.1 -4.5 -0.2 -2.0 0.0 0.0 18.2 0.0 0.0 0.0 18.2 Mechanical Point 84.3 0.0 0.0 3 712.71 -68.1 -4.5 -0.2 -1.9 0.0 0.0 12.5 0.0 0.0 0.0 12.5 Mechanical Point 84.3 0.0 0.0 3 736.76 -68.3 -4.5 -0.2 -2.0 0.0 0.0 12.2 0.0 0.0 0.0 12.2 Mechanical Point 84.3 0.0 0.0 3 722.02 -68.2 -4.5 -0.2 -2.0 0.0 0.0 12.4 0.0 0.0 0.0 12.4 Mechanical Point 84.3 0.0 0.0 3 730.52 -68.3 -4.5 -0.2 -2.0 0.0 0.0 12.3 0.0 0.0 0.0 12.3 Mechanical Point 84.3 0.0 0.0 3 592.85 -66.5 -4.5 -0.3 -1.6 0.0 0.0 14.5 0.0 0.0 0.0 14.5 Mechanical Point 84.3 0.0 0.0 3 677.48 -67.6 -4.5 -0.3 -1.9 0.0 0.0 13.1 0.0 0.0 0.0 13.1 Mechanical Point 84.3 0.0 0.0 3 641.84 -67.1 -4.5 -0.3 -1.8 0.0 0.0 13.6 0.0 0.0 0.0 13.6 Mechanical Point 84.3 0.0 0.0 3 713.77 -68.1 -4.5 -0.2 -2.0 0.0 0.0 12.5 0.0 0.0 0.0 12.5 Mechanical Point 84.3 0.0 0.0 3 660.42 -67.4 -4.5 -0.3 -1.8 0.0 0.0 13.3 0.0 0.0 0.0 13.3 Mechanical Point 84.3 0.0 0.0 3 634.57 -67.0 -4.5 -0.3 -1.7 0.0 0.0 13.8 0.0 0.0 0.0 13.8 Mechanical Point 84.3 0.0 0.0 3 620.50 -66.8 -4.5 -0.3 -1.7 0.0 0.0 14.0 0.0 0.0 0.0 14.0 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
1972
Costco Foothill Ranch
Mean propagation Leq - 01 Mechanical
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Mechanical Point 84.3 0.0 0.0 3 606.06 -66.6 -4.5 -0.3 -1.7 0.0 0.0 14.2 0.0 0.0 0.0 14.2 Mechanical Point 84.3 0.0 0.0 3 626.72 -66.9 -4.5 -0.3 -1.7 0.0 0.0 13.9 0.0 0.0 0.0 13.9 Mechanical Point 84.3 0.0 0.0 3 651.19 -67.3 -4.5 -0.3 -1.8 0.0 0.0 13.5 0.0 0.0 0.0 13.5 Mechanical Point 84.3 0.0 0.0 3 677.95 -67.6 -4.5 -0.3 -1.9 0.0 0.0 13.1 0.0 0.0 0.0 13.1 Mechanical Point 84.3 0.0 0.0 3 673.71 -67.6 -4.5 -0.3 -1.8 0.0 0.0 13.1 0.0 0.0 0.0 13.1 Mechanical Point 84.3 0.0 0.0 3 702.99 -67.9 -4.5 -0.2 -1.9 0.0 0.0 12.7 0.0 0.0 0.0 12.7 Mechanical (Condenser) Point 98.0 0.0 0.0 3 720.35 -68.1 -4.5 -0.2 -2.0 0.0 0.0 26.1 0.0 0.0 0.0 26.1 Mechanical (Condenser) Point 98.0 0.0 0.0 3 730.56 -68.3 -4.5 -0.2 -2.0 0.0 0.0 26.0 0.0 0.0 0.0 26.0 Receiver R3 Leq,d 31.7 dB(A)
Emergency Generator Point 90.0 0.0 0.0 3 629.07 -67.0 -4.5 -0.7 -1.7 0.0 0.0 19.1 0.0 0.0 0.0 19.1 Mechanical Point 84.3 0.0 0.0 3 606.33 -66.6 -4.5 -1.0 -1.7 0.0 0.0 13.5 0.0 0.0 0.0 13.5 Mechanical Point 84.3 0.0 0.0 3 611.85 -66.7 -4.5 -1.2 -1.7 0.0 0.0 13.3 0.0 0.0 0.0 13.3 Mechanical Point 84.3 0.0 0.0 3 601.87 -66.6 -4.5 -1.2 -1.6 0.0 0.0 13.4 0.0 0.0 0.0 13.4 Mechanical Point 84.3 0.0 0.0 3 592.45 -66.4 -4.5 -1.6 -1.6 0.0 0.0 13.1 0.0 0.0 0.0 13.1 Mechanical Point 84.3 0.0 0.0 3 568.64 -66.1 -4.5 -3.2 -1.6 0.0 0.0 12.0 0.0 0.0 0.0 12.0 Mechanical Point 84.3 0.0 0.0 3 559.05 -65.9 -4.5 -1.5 -1.5 0.0 0.0 13.9 0.0 0.0 0.0 13.9 Mechanical Point 84.3 0.0 0.0 3 550.99 -65.8 -4.4 -1.5 -1.5 0.0 0.0 14.1 0.0 0.0 0.0 14.1 Mechanical Point 84.3 0.0 0.0 3 648.49 -67.2 -4.5 -0.6 -1.8 0.0 0.0 13.2 0.0 0.0 0.0 13.2 Mechanical Point 84.3 0.0 0.0 3 538.17 -65.6 -4.4 -1.8 -1.5 0.0 0.0 13.9 0.0 0.0 0.0 13.9 Mechanical Point 84.3 0.0 0.0 3 525.13 -65.4 -4.4 -2.3 -1.4 0.0 0.0 13.7 0.0 0.0 0.0 13.7 Mechanical Point 84.3 0.0 0.0 3 531.50 -65.5 -4.4 -3.0 -1.5 0.0 0.0 13.0 0.0 0.0 0.0 13.0 Mechanical Point 84.3 0.0 0.0 3 548.49 -65.8 -4.4 -3.2 -1.5 0.0 0.0 12.4 0.0 0.0 0.0 12.4 Mechanical Point 84.3 0.0 0.0 3 563.84 -66.0 -4.5 -1.6 -1.5 0.0 0.0 13.7 0.0 0.0 0.0 13.7 Mechanical Point 84.3 0.0 0.0 3 594.41 -66.5 -4.5 -0.9 -1.6 0.0 0.0 13.8 0.0 0.0 0.0 13.8 Mechanical Point 84.3 0.0 0.0 3 600.19 -66.6 -4.5 -0.9 -1.6 0.0 0.0 13.8 0.0 0.0 0.0 13.8 Mechanical Point 84.3 0.0 0.0 3 577.44 -66.2 -4.5 -1.1 -1.6 0.0 0.0 13.9 0.0 0.0 0.0 13.9 Mechanical Point 84.3 0.0 0.0 3 570.05 -66.1 -4.5 -1.7 -1.6 0.0 0.0 13.5 0.0 0.0 0.0 13.5 Mechanical (Condenser) Point 98.0 0.0 0.0 3 620.30 -66.8 -4.5 -0.9 -1.7 0.0 0.0 27.1 0.0 0.0 0.0 27.1 Mechanical (Condenser) Point 98.0 0.0 0.0 3 619.92 -66.8 -4.5 -0.9 -1.7 0.0 0.0 27.0 0.0 0.0 0.0 27.0 Receiver R4 Leq,d 31.4 dB(A)
Emergency Generator Point 90.0 0.0 0.0 3 688.99 -67.8 -4.5 -0.2 -1.9 0.0 0.0 18.6 0.0 0.0 0.0 18.6 Mechanical Point 84.3 0.0 0.0 3 670.50 -67.5 -4.5 -0.3 -1.8 0.0 0.0 13.2 0.0 0.0 0.0 13.2 Mechanical Point 84.3 0.0 0.0 3 654.13 -67.3 -4.5 -0.3 -1.8 0.0 0.0 13.4 0.0 0.0 0.0 13.4 Mechanical Point 84.3 0.0 0.0 3 658.64 -67.4 -4.5 -0.3 -1.8 0.0 0.0 13.4 0.0 0.0 0.0 13.4 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 2
1973
Costco Foothill Ranch
Mean propagation Leq - 01 Mechanical
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Mechanical Point 84.3 0.0 0.0 3 643.31 -67.2 -4.5 -0.3 -1.8 0.0 0.0 13.6 0.0 0.0 0.0 13.6 Mechanical Point 84.3 0.0 0.0 3 741.01 -68.4 -4.5 -0.2 -2.0 0.0 0.0 12.1 0.0 0.0 0.0 12.1 Mechanical Point 84.3 0.0 0.0 3 664.03 -67.4 -4.5 -0.3 -1.8 0.0 0.0 13.3 0.0 0.0 0.0 13.3 Mechanical Point 84.3 0.0 0.0 3 688.76 -67.8 -4.5 -0.2 -1.9 0.0 0.0 12.9 0.0 0.0 0.0 12.9 Mechanical Point 84.3 0.0 0.0 3 706.47 -68.0 -4.5 -0.2 -1.9 0.0 0.0 12.6 0.0 0.0 0.0 12.6 Mechanical Point 84.3 0.0 0.0 3 664.22 -67.4 -4.5 -0.3 -1.8 0.0 0.0 13.3 0.0 0.0 0.0 13.3 Mechanical Point 84.3 0.0 0.0 3 677.94 -67.6 -4.5 -0.3 -1.9 0.0 0.0 13.1 0.0 0.0 0.0 13.1 Mechanical Point 84.3 0.0 0.0 3 693.83 -67.8 -4.5 -0.2 -1.9 0.0 0.0 12.8 0.0 0.0 0.0 12.8 Mechanical Point 84.3 0.0 0.0 3 716.74 -68.1 -4.5 -0.2 -2.0 0.0 0.0 12.5 0.0 0.0 0.0 12.5 Mechanical Point 84.3 0.0 0.0 3 710.29 -68.0 -4.5 -0.2 -1.9 0.0 0.0 12.6 0.0 0.0 0.0 12.6 Mechanical Point 84.3 0.0 0.0 3 712.83 -68.1 -4.5 -0.2 -1.9 0.0 0.0 12.5 0.0 0.0 0.0 12.5 Mechanical Point 84.3 0.0 0.0 3 695.14 -67.8 -4.5 -0.2 -1.9 0.0 0.0 12.8 0.0 0.0 0.0 12.8 Mechanical Point 84.3 0.0 0.0 3 680.93 -67.7 -4.5 -0.3 -1.9 0.0 0.0 13.0 0.0 0.0 0.0 13.0 Mechanical Point 84.3 0.0 0.0 3 649.94 -67.2 -4.5 -0.3 -1.8 0.0 0.0 13.5 0.0 0.0 0.0 13.5 Mechanical (Condenser) Point 98.0 0.0 0.0 3 675.80 -67.6 -4.5 -0.3 -1.8 0.0 0.0 26.8 0.0 0.0 0.0 26.8 Mechanical (Condenser) Point 98.0 0.0 0.0 3 666.58 -67.5 -4.5 -0.3 -1.8 0.0 0.0 26.9 0.0 0.0 0.0 26.9 Receiver R5 Leq,d 39.4 dB(A)
Emergency Generator Point 90.0 0.0 0.0 3 238.55 -58.5 -4.0 -2.5 -0.7 0.0 0.0 27.4 0.0 0.0 0.0 27.4 Mechanical Point 84.3 0.0 0.0 3 259.15 -59.3 -4.0 -2.7 -0.7 0.0 0.0 20.6 0.0 0.0 0.0 20.6 Mechanical Point 84.3 0.0 0.0 3 250.33 -59.0 -4.0 -2.1 -0.7 0.0 0.0 21.5 0.0 0.0 0.0 21.5 Mechanical Point 84.3 0.0 0.0 3 261.59 -59.3 -4.0 -2.6 -0.7 0.0 0.0 20.6 0.0 0.0 0.0 20.6 Mechanical Point 84.3 0.0 0.0 3 269.65 -59.6 -4.1 -2.5 -0.7 0.0 0.0 20.4 0.0 0.0 0.0 20.4 Mechanical Point 84.3 0.0 0.0 3 343.50 -61.7 -4.2 -1.7 -0.9 0.0 0.0 18.8 0.0 0.0 0.0 18.8 Mechanical Point 84.3 0.0 0.0 3 310.71 -60.8 -4.2 -3.5 -0.8 0.0 0.0 17.9 0.0 0.0 0.0 17.9 Mechanical Point 84.3 0.0 0.0 3 330.62 -61.4 -4.2 -3.9 -0.9 0.0 0.0 16.9 0.0 0.0 0.0 16.9 Mechanical Point 84.3 0.0 0.0 3 222.09 -57.9 -3.9 -2.1 -0.6 0.0 0.0 22.7 0.0 0.0 0.0 22.7 Mechanical Point 84.3 0.0 0.0 3 334.62 -61.5 -4.2 -3.8 -0.9 0.0 0.0 16.9 0.0 0.0 0.0 16.9 Mechanical Point 84.3 0.0 0.0 3 355.71 -62.0 -4.2 -4.0 -1.0 0.0 0.0 16.1 0.0 0.0 0.0 16.1 Mechanical Point 84.3 0.0 0.0 3 356.62 -62.0 -4.2 -4.1 -1.0 0.0 0.0 16.0 0.0 0.0 0.0 16.0 Mechanical Point 84.3 0.0 0.0 3 350.49 -61.9 -4.2 -3.1 -1.0 0.0 0.0 17.2 0.0 0.0 0.0 17.2 Mechanical Point 84.3 0.0 0.0 3 327.39 -61.3 -4.2 -3.3 -0.9 0.0 0.0 17.6 0.0 0.0 0.0 17.6 Mechanical Point 84.3 0.0 0.0 3 291.37 -60.3 -4.1 -3.1 -0.8 0.0 0.0 19.0 0.0 0.0 0.0 19.0 Mechanical Point 84.3 0.0 0.0 3 275.01 -59.8 -4.1 -3.4 -0.8 0.0 0.0 19.3 0.0 0.0 0.0 19.3 Mechanical Point 84.3 0.0 0.0 3 295.76 -60.4 -4.1 -3.5 -0.8 0.0 0.0 18.4 0.0 0.0 0.0 18.4 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 3
1974
Costco Foothill Ranch
Mean propagation Leq - 01 Mechanical
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Mechanical Point 84.3 0.0 0.0 3 294.60 -60.4 -4.1 -3.2 -0.8 0.0 0.0 18.8 0.0 0.0 0.0 18.8 Mechanical (Condenser) Point 98.0 0.0 0.0 3 244.81 -58.8 -4.0 -2.4 -0.7 0.0 0.0 35.2 0.0 0.0 0.0 35.2 Mechanical (Condenser) Point 98.0 0.0 0.0 3 243.35 -58.7 -4.0 -2.2 -0.7 0.0 0.0 35.5 0.0 0.0 0.0 35.5 Receiver R6 Leq,d 38.3 dB(A)
Emergency Generator Point 90.0 0.0 0.0 3 340.50 -61.6 -4.2 -0.5 -0.9 0.0 0.0 25.7 0.0 0.0 0.0 25.7 Mechanical Point 84.3 0.0 0.0 3 346.35 -61.8 -4.2 -0.5 -0.9 0.0 0.0 19.8 0.0 0.0 0.0 19.8 Mechanical Point 84.3 0.0 0.0 3 370.03 -62.4 -4.3 -0.5 -1.0 0.0 0.0 19.2 0.0 0.0 0.0 19.2 Mechanical Point 84.3 0.0 0.0 3 357.63 -62.1 -4.3 -0.5 -1.0 0.0 0.0 19.5 0.0 0.0 0.0 19.5 Mechanical Point 84.3 0.0 0.0 3 369.77 -62.4 -4.3 -0.5 -1.0 0.0 0.0 19.2 0.0 0.0 0.0 19.2 Mechanical Point 84.3 0.0 0.0 3 240.94 -58.6 -4.0 -0.8 -0.7 0.0 0.0 23.3 0.0 0.0 0.0 23.3 Mechanical Point 84.3 0.0 0.0 3 327.30 -61.3 -4.2 -0.6 -0.9 0.0 0.0 20.3 0.0 0.0 0.0 20.3 Mechanical Point 84.3 0.0 0.0 3 295.53 -60.4 -4.1 -0.7 -0.8 0.0 0.0 21.3 0.0 0.0 0.0 21.3 Mechanical Point 84.3 0.0 0.0 3 334.87 -61.5 -4.2 -0.6 -0.9 0.0 0.0 20.1 0.0 0.0 0.0 20.1 Mechanical Point 84.3 0.0 0.0 3 319.26 -61.1 -4.2 -0.6 -0.9 0.0 0.0 20.6 0.0 0.0 0.0 20.6 Mechanical Point 84.3 0.0 0.0 3 300.69 -60.6 -4.1 -1.0 -0.8 0.0 0.0 20.8 0.0 0.0 0.0 20.8 Mechanical Point 84.3 0.0 0.0 3 284.59 -60.1 -4.1 -1.1 -0.8 0.0 0.0 21.2 0.0 0.0 0.0 21.2 Mechanical Point 84.3 0.0 0.0 3 262.95 -59.4 -4.0 -0.7 -0.7 0.0 0.0 22.4 0.0 0.0 0.0 22.4 Mechanical Point 84.3 0.0 0.0 3 275.20 -59.8 -4.1 -0.7 -0.8 0.0 0.0 22.0 0.0 0.0 0.0 22.0 Mechanical Point 84.3 0.0 0.0 3 286.89 -60.1 -4.1 -0.7 -0.8 0.0 0.0 21.6 0.0 0.0 0.0 21.6 Mechanical Point 84.3 0.0 0.0 3 312.18 -60.9 -4.2 -0.6 -0.9 0.0 0.0 20.8 0.0 0.0 0.0 20.8 Mechanical Point 84.3 0.0 0.0 3 316.21 -61.0 -4.2 -0.6 -0.9 0.0 0.0 20.7 0.0 0.0 0.0 20.7 Mechanical Point 84.3 0.0 0.0 3 349.02 -61.8 -4.2 -0.5 -1.0 0.0 0.0 19.7 0.0 0.0 0.0 19.7 Mechanical (Condenser) Point 98.0 0.0 0.0 3 349.97 -61.9 -4.2 -0.5 -1.0 0.0 0.0 33.4 0.0 0.0 0.0 33.4 Mechanical (Condenser) Point 98.0 0.0 0.0 3 360.93 -62.1 -4.3 -0.5 -1.0 0.0 0.0 33.1 0.0 0.0 0.0 33.1 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 4
1975
2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
2/Mechanical 4/Mechanical 5/Mechanical
6/Mechanical
3/Mechanical
7/Mechanical
8/Mechanical 9/Mechanical
10/Mechanical
11/Mechanical
13/Mechanical (Condenser) 12/Mechanical 14/Mechanical 15/Mechanical 19/Mechanical
21/Mechanical (Condenser) 22/Emergency Generator
23/Mechanical
24/Mechanical
4/Mechanical
Noise levelLeq (dBA)
<= 6
6 < <= 12
12 < <= 1818 < <= 2424 < <= 3030 < <= 3636 < <= 4242 < <= 4848 < <= 5454 < <= 6060 < <= 6666 < <= 7272 < <= 7878 < Signs and symbols
Point sourceMain buildingReceiver
Costco Foothill Ranch ProjectNoise Contours: Mechanical Equipment 1976
Costco Foothill Ranch
Source Levels in dB(A) - 02 Loading
Name Source type Lw
dB(A)
Loading Dock 1 Point 102.4
Loading Dock 2 Point 102.4
Loading Dock 3 Point 102.4
Loading Dock 4 Point 102.4
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1977
Costco Foothill Ranch
Mean propagation Leq - 02 Loading
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Receiver R1 Leq,d 15.0 dB(A)
Loading Dock 1 Point 102.4 0.0 0.0 0 608.75 -66.7 4.2 -24.9 -6.1 0.0 0.0 8.9 0.0 0.0 0.0 8.9 Loading Dock 2 Point 102.4 0.0 0.0 0 607.00 -66.7 4.2 -24.9 -6.0 0.0 0.0 9.0 0.0 0.0 0.0 9.0 Loading Dock 3 Point 102.4 0.0 0.0 0 605.24 -66.6 4.2 -24.9 -6.0 0.0 0.0 9.0 0.0 0.0 0.0 9.0 Loading Dock 4 Point 102.4 0.0 0.0 0 603.56 -66.6 4.2 -24.9 -6.0 0.0 0.0 9.0 0.0 0.0 0.0 9.0 Receiver R2 Leq,d 12.8 dB(A)
Loading Dock 1 Point 102.4 0.0 0.0 0 747.98 -68.5 4.2 -24.8 -6.7 0.0 0.0 6.7 0.0 0.0 0.0 6.7 Loading Dock 2 Point 102.4 0.0 0.0 0 744.64 -68.4 4.2 -24.8 -6.6 0.0 0.0 6.8 0.0 0.0 0.0 6.8 Loading Dock 3 Point 102.4 0.0 0.0 0 741.38 -68.4 4.2 -24.8 -6.6 0.0 0.0 6.8 0.0 0.0 0.0 6.8 Loading Dock 4 Point 102.4 0.0 0.0 0 738.08 -68.4 4.2 -24.8 -6.6 0.0 0.0 6.8 0.0 0.0 0.0 6.8 Receiver R3 Leq,d 19.6 dB(A)
Loading Dock 1 Point 102.4 0.0 0.0 0 611.09 -66.7 4.2 -23.4 -4.4 0.0 2.6 14.6 0.0 0.0 0.0 14.6 Loading Dock 2 Point 102.4 0.0 0.0 0 607.94 -66.7 4.2 -24.0 -4.9 0.0 2.6 13.7 0.0 0.0 0.0 13.7 Loading Dock 3 Point 102.4 0.0 0.0 0 605.01 -66.6 4.2 -24.3 -5.2 0.0 2.7 13.1 0.0 0.0 0.0 13.1 Loading Dock 4 Point 102.4 0.0 0.0 0 601.90 -66.6 4.2 -24.5 -5.6 0.0 2.7 12.5 0.0 0.0 0.0 12.5 Receiver R4 Leq,d 36.8 dB(A)
Loading Dock 1 Point 102.4 0.0 0.0 0 643.44 -67.2 4.2 -4.8 -6.4 0.0 2.5 30.8 0.0 0.0 0.0 30.8 Loading Dock 2 Point 102.4 0.0 0.0 0 643.71 -67.2 4.2 -4.8 -6.4 0.0 2.5 30.8 0.0 0.0 0.0 30.8 Loading Dock 3 Point 102.4 0.0 0.0 0 644.11 -67.2 4.2 -4.8 -6.4 0.0 2.5 30.8 0.0 0.0 0.0 30.8 Loading Dock 4 Point 102.4 0.0 0.0 0 644.41 -67.2 4.2 -4.8 -6.4 0.0 2.5 30.7 0.0 0.0 0.0 30.7 Receiver R5 Leq,d 25.0 dB(A)
Loading Dock 1 Point 102.4 0.0 0.0 0 250.37 -59.0 3.7 -24.5 -3.3 0.0 0.0 19.2 0.0 0.0 0.0 19.2 Loading Dock 2 Point 102.4 0.0 0.0 0 253.56 -59.1 3.7 -24.5 -3.4 0.0 0.0 19.1 0.0 0.0 0.0 19.1 Loading Dock 3 Point 102.4 0.0 0.0 0 256.55 -59.2 3.7 -24.6 -3.4 0.0 0.0 18.9 0.0 0.0 0.0 18.9 Loading Dock 4 Point 102.4 0.0 0.0 0 259.76 -59.3 3.7 -24.6 -3.5 0.0 0.0 18.8 0.0 0.0 0.0 18.8 Receiver R6 Leq,d 20.8 dB(A)
Loading Dock 1 Point 102.4 0.0 0.0 0 382.18 -62.6 4.0 -24.8 -4.5 0.0 0.4 14.7 0.0 0.0 0.0 14.7 Loading Dock 2 Point 102.4 0.0 0.0 0 379.60 -62.6 4.0 -24.9 -4.5 0.0 0.4 14.8 0.0 0.0 0.0 14.8 Loading Dock 3 Point 102.4 0.0 0.0 0 377.07 -62.5 3.9 -24.9 -4.5 0.0 0.4 14.8 0.0 0.0 0.0 14.8 Loading Dock 4 Point 102.4 0.0 0.0 0 374.57 -62.5 3.9 -24.9 -4.5 0.0 0.4 14.9 0.0 0.0 0.0 14.9 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
1978
15/Loading Dock 1 16/Loading Dock 2 17/Loading Dock 3 18/Loading Dock 4 2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
Noise levelLeq (dBA)
<= 6
6 < <= 12
12 < <= 1818 < <= 2424 < <= 3030 < <= 3636 < <= 4242 < <= 4848 < <= 5454 < <= 6060 < <= 6666 < <= 7272 < <= 7878 < Signs and symbols
Point sourceMain buildingReceiver
Costco Foothill Ranch ProjectNoise Contours: Loading Docks 1979
Costco Foothill Ranch
Source Levels in dB(A) - 03 Trash Compactor
Name Source type Lw
dB(A)
Trash Compactor 1 Point 97.7
Trash Compactor 2 Point 97.7
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1980
Costco Foothill Ranch
Mean propagation Leq - 03 Trash Compactor
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Receiver R1 Leq,d 11.4 dB(A)
Trash Compactor 1 Point 97.7 0.0 0.0 0 596.80 -66.5 4.0 -24.3 -2.8 0.0 0.0 8.1 0.0 0.0 0.0 8.1 Trash Compactor 2 Point 97.7 0.0 0.0 0 594.66 -66.5 4.0 -24.0 -2.5 0.0 0.0 8.7 0.0 0.0 0.0 8.7 Receiver R2 Leq,d 8.7 dB(A)
Trash Compactor 1 Point 97.7 0.0 0.0 0 747.33 -68.5 4.0 -24.4 -3.4 0.0 0.0 5.5 0.0 0.0 0.0 5.5 Trash Compactor 2 Point 97.7 0.0 0.0 0 747.29 -68.5 4.0 -24.2 -3.2 0.0 0.0 5.8 0.0 0.0 0.0 5.8 Receiver R3 Leq,d 11.0 dB(A)
Trash Compactor 1 Point 97.7 0.0 0.0 0 631.11 -67.0 4.0 -23.9 -2.9 0.0 0.0 7.9 0.0 0.0 0.0 7.9 Trash Compactor 2 Point 97.7 0.0 0.0 0 634.84 -67.0 4.0 -23.7 -2.8 0.0 0.0 8.1 0.0 0.0 0.0 8.1 Receiver R4 Leq,d 28.9 dB(A)
Trash Compactor 1 Point 97.7 0.0 0.0 0 661.76 -67.4 4.0 -4.8 -3.6 0.0 0.0 25.9 0.0 0.0 0.0 25.9 Trash Compactor 2 Point 97.7 0.0 0.0 0 665.18 -67.5 4.0 -4.8 -3.6 0.0 0.0 25.9 0.0 0.0 0.0 25.9 Receiver R5 Leq,d 41.6 dB(A)
Trash Compactor 1 Point 97.7 0.0 0.0 0 230.67 -58.3 3.4 -5.3 -1.4 0.0 2.4 38.6 0.0 0.0 0.0 38.6 Trash Compactor 2 Point 97.7 0.0 0.0 0 227.05 -58.1 3.4 -5.3 -1.3 0.0 2.4 38.7 0.0 0.0 0.0 38.7 Receiver R6 Leq,d 16.2 dB(A)
Trash Compactor 1 Point 97.7 0.0 0.0 0 375.44 -62.5 3.8 -24.1 -1.9 0.0 0.0 13.0 0.0 0.0 0.0 13.0 Trash Compactor 2 Point 97.7 0.0 0.0 0 374.33 -62.5 3.8 -23.8 -1.7 0.0 0.0 13.4 0.0 0.0 0.0 13.4 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
1981
13/Trash Compactor 2 12/Trash Compactor 1
2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
Noise levelLeq (dBA)
<= 6
6 < <= 12
12 < <= 1818 < <= 2424 < <= 3030 < <= 3636 < <= 4242 < <= 4848 < <= 5454 < <= 6060 < <= 6666 < <= 7272 < <= 7878 < Signs and symbols
Point sourceMain buildingReceiver
Costco Foothill Ranch ProjectNoise Contours: Trash Compactors 1982
Costco Foothill Ranch
Source Levels in dB(A) - 04 Tire Center
Name Source type Lw
dB(A)
Tire Center Point 96.7
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1983
Costco Foothill Ranch
Mean propagation Leq - 04 Tire Center
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Receiver R1 Leq,d 27.9 dB(A)
Tire Center Point 96.7 0.0 0.0 3 534.04 -65.5 -4.7 -0.1 -1.5 0.0 0.0 27.9 0.0 0.0 0.0 27.9 Receiver R2 Leq,d 29.0 dB(A)
Tire Center Point 96.7 0.0 0.0 3 613.17 -66.7 -4.7 -0.1 -1.7 0.0 2.5 29.0 0.0 0.0 0.0 29.0 Receiver R3 Leq,d 30.0 dB(A)
Tire Center Point 96.7 0.0 0.0 3 521.88 -65.3 -4.7 -0.8 -1.4 0.0 2.5 30.0 0.0 0.0 0.0 30.0 Receiver R4 Leq,d 9.0 dB(A)
Tire Center Point 96.7 0.0 0.0 3 693.96 -67.8 -4.7 -16.3 -1.9 0.0 0.0 9.0 0.0 0.0 0.0 9.0 Receiver R5 Leq,d 11.5 dB(A)
Tire Center Point 96.7 0.0 0.0 3 368.07 -62.3 -4.7 -20.3 -1.0 0.0 0.0 11.5 0.0 0.0 0.0 11.5 Receiver R6 Leq,d 32.7 dB(A)
Tire Center Point 96.7 0.0 0.0 3 282.74 -60.0 -4.6 -1.6 -0.8 0.0 0.0 32.7 0.0 0.0 0.0 32.7 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
1984
8/Tire Center
2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
Noise level
Leq (dBA)
<= 6
6 < <= 12
12 < <= 18
18 < <= 24
24 < <= 30
30 < <= 36
36 < <= 42
42 < <= 48
48 < <= 54
54 < <= 60
60 < <= 66
66 < <= 72
72 < <= 78
78 <
Signs and symbols
Point source
Main building
Receiver
Costco Foothill Ranch Project
Noise Contours: Tire Center
Item: 11
1985
Costco Foothill Ranch
Input data parking lots - 05 Parking Lot
Parking lot Number of
Parking Spaces
Parking Lot A 50
Parking Lot B 219
Parking Lot C 644
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1986
Costco Foothill Ranch
Mean propagation Leq - 05 Parking Lot
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Receiver R1 Leq,d 33.1 dB(A)
Parking Lot A PLot 89.0 1294.3 0.0 0.0 0 533.89 -65.5 3.4 -12.3 -1.0 0.0 1.4 15.0 0.0 0.0 0.0 15.0 Parking Lot B PLot 97.2 10009.5 0.0 0.0 0 643.00 -67.2 3.4 -11.2 -1.9 0.0 0.0 20.3 0.0 0.0 0.0 20.3 Parking Lot C PLot 103.1 23629.1 0.0 0.0 0 521.54 -65.3 3.4 -6.7 -1.7 0.0 0.0 32.8 0.0 0.0 0.0 32.8 Receiver R2 Leq,d 34.2 dB(A)
Parking Lot A PLot 89.0 1294.3 0.0 0.0 0 703.51 -67.9 3.4 -8.4 -1.7 0.0 0.8 15.2 0.0 0.0 0.0 15.2 Parking Lot B PLot 97.2 10009.5 0.0 0.0 0 724.50 -68.2 3.4 -6.5 -2.2 0.0 0.0 23.7 0.0 0.0 0.0 23.7 Parking Lot C PLot 103.1 23629.1 0.0 0.0 0 565.56 -66.0 3.4 -5.0 -1.9 0.0 0.1 33.7 0.0 0.0 0.0 33.7 Receiver R3 Leq,d 35.2 dB(A)
Parking Lot A PLot 89.0 1294.3 0.0 0.0 0 662.28 -67.4 3.4 -19.6 -0.9 0.0 0.3 4.9 0.0 0.0 0.0 4.9 Parking Lot B PLot 97.2 10009.5 0.0 0.0 0 505.62 -65.1 3.5 -5.7 -1.6 0.0 0.1 28.4 0.0 0.0 0.0 28.4 Parking Lot C PLot 103.1 23629.1 0.0 0.0 0 466.59 -64.4 3.5 -6.9 -1.1 0.0 0.0 34.2 0.0 0.0 0.0 34.2 Receiver R4 Leq,d 36.7 dB(A)
Parking Lot A PLot 89.0 1294.3 0.0 0.0 0 726.59 -68.2 3.4 -6.3 -2.4 0.0 0.1 15.5 0.0 0.0 0.0 15.5 Parking Lot B PLot 97.2 10009.5 0.0 0.0 0 586.47 -66.4 3.4 -3.3 -2.2 0.0 0.3 29.1 0.0 0.0 0.0 29.1 Parking Lot C PLot 103.1 23629.1 0.0 0.0 0 692.85 -67.8 3.4 -0.2 -2.6 0.0 0.0 35.9 0.0 0.0 0.0 35.9 Receiver R5 Leq,d 34.4 dB(A)
Parking Lot A PLot 89.0 1294.3 0.0 0.0 0 209.67 -57.4 3.3 -5.2 -0.9 0.0 0.7 29.4 0.0 0.0 0.0 29.4 Parking Lot B PLot 97.2 10009.5 0.0 0.0 0 347.82 -61.8 3.5 -7.6 -1.3 0.0 0.0 30.0 0.0 0.0 0.0 30.0 Parking Lot C PLot 103.1 23629.1 0.0 0.0 0 434.03 -63.7 3.5 -12.8 -0.7 0.0 0.1 29.5 0.0 0.0 0.0 29.5 Receiver R6 Leq,d 44.5 dB(A)
Parking Lot A PLot 89.0 1294.3 0.0 0.0 0 319.05 -61.1 3.5 -6.8 -1.0 0.0 1.6 25.1 0.0 0.0 0.0 25.1 Parking Lot B PLot 97.2 10009.5 0.0 0.0 0 396.21 -63.0 3.5 -9.9 -0.8 0.0 0.3 27.5 0.0 0.0 0.0 27.5 Parking Lot C PLot 103.1 23629.1 0.0 0.0 0 252.45 -59.0 3.3 -2.3 -1.1 0.0 0.3 44.3 0.0 0.0 0.0 44.3 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
1987
2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
Noise levelLeq (dBA)
<= 6
6 < <= 12
12 < <= 1818 < <= 2424 < <= 3030 < <= 3636 < <= 4242 < <= 4848 < <= 5454 < <= 6060 < <= 6666 < <= 7272 < <= 7878 < Signs and symbols
Point sourceMain buildingReceiverParking lot
Costco Foothill Ranch ProjectNoise Contours: Parking Lot 1988
Costco Foothill Ranch
Source Levels in dB(A) - 06 Parking Sweper
Name Source type Lw
dB(A)
Parking Sweeper A Area 103.7
Parking Sweeper B Area 103.7
Parking Sweeper C Area 103.7
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1989
Costco Foothill Ranch
Mean propagation Leq - 06 Parking Sweper
Source Source type Lw
dB(A)
l or A
m,m²
KI
dB
KT
dB
KodB
S
m
Adiv
dB
Agr
dB
Abar
dB
Aatm
dB
ADI
dB
dLrefl
dB(A)
Ls
dB(A)
dLw
dB
Cmet
dB
ZR
dB
Lr
dB(A)
Receiver R1 Leq,d 33.1 dB(A)
Parking Sweeper A Area 103.7 1294.3 0.0 0.0 0 533.89 -65.5 2.9 -14.6 -2.2 0.0 2.2 26.4 0.0 0.0 0.0 26.4 Parking Sweeper B Area 103.7 10009.4 0.0 0.0 0 643.02 -67.2 2.9 -12.0 -3.2 0.0 0.0 24.3 0.0 0.0 0.0 24.3 Parking Sweeper C Area 103.7 23629.1 0.0 0.0 0 521.54 -65.3 2.9 -7.4 -2.7 0.0 0.0 31.3 0.0 0.0 0.0 31.3 Receiver R2 Leq,d 34.8 dB(A)
Parking Sweeper A Area 103.7 1294.3 0.0 0.0 0 703.51 -67.9 2.9 -9.4 -3.1 0.0 1.9 28.1 0.0 0.0 0.0 28.1 Parking Sweeper B Area 103.7 10009.4 0.0 0.0 0 724.46 -68.2 3.0 -7.0 -3.5 0.0 0.0 27.9 0.0 0.0 0.0 27.9 Parking Sweeper C Area 103.7 23629.1 0.0 0.0 0 565.55 -66.0 2.9 -5.6 -2.9 0.0 0.3 32.4 0.0 0.0 0.0 32.4 Receiver R3 Leq,d 35.8 dB(A)
Parking Sweeper A Area 103.7 1294.3 0.0 0.0 0 662.22 -67.4 2.9 -23.1 -2.5 0.0 1.7 15.4 0.0 0.0 0.0 15.4 Parking Sweeper B Area 103.7 10009.4 0.0 0.0 0 505.56 -65.1 2.9 -6.1 -2.5 0.0 0.1 33.1 0.0 0.0 0.0 33.1 Parking Sweeper C Area 103.7 23629.1 0.0 0.0 0 466.64 -64.4 2.9 -7.8 -2.1 0.0 0.1 32.4 0.0 0.0 0.0 32.4 Receiver R4 Leq,d 38.2 dB(A)
Parking Sweeper A Area 103.7 1294.3 0.0 0.0 0 726.59 -68.2 3.0 -6.9 -3.7 0.0 0.1 27.9 0.0 0.0 0.0 27.9 Parking Sweeper B Area 103.7 10009.4 0.0 0.0 0 586.47 -66.4 2.9 -3.5 -3.1 0.0 0.7 34.3 0.0 0.0 0.0 34.3 Parking Sweeper C Area 103.7 23629.1 0.0 0.0 0 692.85 -67.8 2.9 -0.2 -3.6 0.0 0.0 35.1 0.0 0.0 0.0 35.1 Receiver R5 Leq,d 43.9 dB(A)
Parking Sweeper A Area 103.7 1294.3 0.0 0.0 0 209.67 -57.4 2.6 -5.4 -1.2 0.0 1.0 43.2 0.0 0.0 0.0 43.2 Parking Sweeper B Area 103.7 10009.4 0.0 0.0 0 347.83 -61.8 2.8 -7.9 -1.8 0.0 0.0 35.0 0.0 0.0 0.0 35.0 Parking Sweeper C Area 103.7 23629.1 0.0 0.0 0 434.04 -63.7 2.9 -15.4 -1.7 0.0 0.3 26.0 0.0 0.0 0.0 26.0 Receiver R6 Leq,d 44.9 dB(A)
Parking Sweeper A Area 103.7 1294.3 0.0 0.0 0 319.05 -61.1 2.8 -7.7 -1.5 0.0 2.0 38.1 0.0 0.0 0.0 38.1 Parking Sweeper B Area 103.7 10009.4 0.0 0.0 0 396.23 -63.0 2.8 -11.7 -1.7 0.0 0.6 30.9 0.0 0.0 0.0 30.9 Parking Sweeper C Area 103.7 23629.1 0.0 0.0 0 252.45 -59.0 2.7 -2.6 -1.5 0.0 0.4 43.6 0.0 0.0 0.0 43.6 SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
1990
2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
Noise levelLeq (dBA)
<= 6
6 < <= 12
12 < <= 1818 < <= 2424 < <= 3030 < <= 3636 < <= 4242 < <= 4848 < <= 5454 < <= 6060 < <= 6666 < <= 7272 < <= 7878 < Signs and symbols
Point sourceMain buildingReceiverArea source
Costco Foothill Ranch ProjectNoise Contours: Parking Lot Sweeper 1991
Costco Foothill Ranch
Emission calculation road - 07 Delivery Truck
Road Vehicle Trips
Per Hour
(Veh/h), Daytime
Vehicle Trips
Per Hour
(Veh/h), Nighttime
Delivery Trucks - Incoming 2.00 2.00
Delivery Trucks - Outgoing 2.00 2.00
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1992
Costco Foothill Ranch
Calculated Noise Levels - 07 Delivery Truck
Source Source type Leq,d
dB(A)
Receiver R1 Leq,d 26.0 dB(A)
Delivery Trucks - Incoming Road 23.4
Delivery Trucks - Outgoing Road 22.5
Receiver R2 Leq,d 35.6 dB(A)
Delivery Trucks - Incoming Road 32.7
Delivery Trucks - Outgoing Road 32.3
Receiver R3 Leq,d 49.3 dB(A)
Delivery Trucks - Incoming Road 47.0
Delivery Trucks - Outgoing Road 45.3
Receiver R4 Leq,d 40.9 dB(A)
Delivery Trucks - Incoming Road 38.1
Delivery Trucks - Outgoing Road 37.6
Receiver R5 Leq,d 30.2 dB(A)
Delivery Trucks - Incoming Road 28.6
Delivery Trucks - Outgoing Road 25.2
Receiver R6 Leq,d 39.3 dB(A)
Delivery Trucks - Incoming Road 36.2
Delivery Trucks - Outgoing Road 36.4
SoundPLAN 8.2
AES 22801 Crespi St Woodland Hills, CA 91364 USA 1
Item: 11
1993
2/R1
3/R2
4/R3
5/R4
6/R5
7/R6
Noise level
Leq (dBA)
<= 6
6 < <= 12
12 < <= 18
18 < <= 24
24 < <= 30
30 < <= 36
36 < <= 42
42 < <= 48
48 < <= 54
54 < <= 60
60 < <= 66
66 < <= 72
72 < <= 78
78 <
Signs and symbols
Point source
Main building
Receiver
Area source
Road
Road axis
Emission line
Surface
Costco Foothill Ranch Project
Noise Contours: Delivery Trucks
Item: 11
1994
A E S
Acoustical Engineering Services
Off-Site Traffic Noise CalculationsProject: Costco Foothill Ranch Project Traffic Distribution as % of ADT
Vehicle Type Day Eve Night Sub totalAuto 77.6% 9.7% 9.7% 97.0% PHV to Medium Truck 1.6% 0.2% 0.2% 2.0% ADT factorHeavy Truck 0.8% 0.1% 0.1% 1.0% 10%

80.0% 10.0% 10.0% 100.0%
EXISTING CONDITIONS Distance to Distance to Site
Roadway Edge of Centerline, Speed Traffic Volume PHV to Barrier Adjust., 24-Hour Roadway Segment Width*, ft Roadway, ft feet mph PHV ADT ADT factor Atten. dBA CNEL Alton Parkway
- West of Ranch Pkwy 100 20 70 50 1,269 12,690 10% 0 0 68.1- Between Ranch Pkwy and Town Centre Dr 100 20 70 50 1,196 11,960 10% 0 0 67.8 - Between Towne Centre Dr and Portola Pkwy 90 20 65 50 808 8,080 10% 0 0 66.4- East of Portola Pkwy 70 20 55 50 339 3,390 10% 0 0 63.5 Bake Parkway
- West of Towne Centre Dr 80 20 60 45 974 9,740 10% 0 0 66.2- Between Towne Centre Dr and Portola Pkwy 80 20 60 45 1,213 12,130 10% 0 0 67.2- East of Portola Pkwy 80 20 60 45 1,179 11,790 10% 0 0 67.1 Ranch Parkway
- North of Alton Pkwy 80 20 60 45 195 1,950 10% 0 0 59.3- South of Alton Pkway 80 20 60 45 209 2,090 10% 0 0 59.6 Towne Centre Drive
- Between Alton Pkwy and Bake Pkwy 80 25 65 35 788 7,880 10% 0 0 62.0 Portola Parkway
- North of Alton Pkwy 100 20 70 45 345 3,450 10% 0 0 61.1- Between Alton Pkwy and Bake Pkwy 100 20 70 45 1,242 12,420 10% 0 0 66.7 - South of Bake Pkwy 100 20 70 45 1,603 16,030 10% 0 0 67.8 * Estimated based on Google Earth map.** Calculated using FHWA's TNM Version 2.5 Computer Noise Model.

Date Printed: 11/21/2025
1995
A E S
Acoustical Engineering Services
Off-Site Traffic Noise CalculationsProject: Costco Foothill Ranch Project Traffic Distribution as % of ADT
Vehicle Type Day Eve Night Sub totalAuto 77.6% 9.7% 9.7% 97.0% PHV to Medium Truck 1.6% 0.2% 0.2% 2.0% ADT factorHeavy Truck 0.8% 0.1% 0.1% 1.0% 10%

80.0% 10.0% 10.0% 100.0%
EXISTING + PROJECT CONDITIONS Distance to Distance to Site Roadway Edge of Centerline, Speed Traffic Volume PHV to Barrier Adjust., 24-Hour Roadway Segment Width*, ft Roadway, ft feet mph PHV ADT ADT factor Atten. dBA CNEL Alton Parkway
- West of Ranch Pkwy 100 20 70 50 1,493 14,930 10% 0 0 68.8- Between Ranch Pkwy and Town Centre Dr 100 20 70 50 1,541 15,410 10% 0 0 68.9 - Between Towne Centre Dr and Portola Pkwy 90 20 65 50 871 8,710 10% 0 0 66.8- East of Portola Pkwy 70 20 55 50 370 3,700 10% 0 0 63.8 Bake Parkway
- West of Towne Centre Dr 80 20 60 45 1,268 12,680 10% 0 0 67.4 - Between Towne Centre Dr and Portola Pkwy 80 20 60 45 1,283 12,830 10% 0 0 67.4- East of Portola Pkwy 80 20 60 45 1,473 14,730 10% 0 0 68.0 Ranch Parkway
- North of Alton Pkwy 80 20 60 45 195 1,950 10% 0 0 59.3- South of Alton Pkway 80 20 60 45 231 2,310 10% 0 0 60.0 Towne Centre Drive
- Between Alton Pkwy and Bake Pkwy 80 25 65 35 1,440 14,400 10% 0 0 64.6 Portola Parkway
- North of Alton Pkwy 100 20 70 45 377 3,770 10% 0 0 61.5- Between Alton Pkwy and Bake Pkwy 100 20 70 45 1,242 12,420 10% 0 0 66.7 - South of Bake Pkwy 100 20 70 45 1,832 18,320 10% 0 0 68.4 * Estimated based on Google Earth map.** Calculated using FHWA's TNM Version 2.5 Computer Noise Model.

Date Printed: 11/21/2025
1996
A E S
Acoustical Engineering Services
Off-Site Traffic Noise CalculationsProject: Costco Foothill Ranch Project Traffic Distribution as % of ADT
Vehicle Type Day Eve Night Sub totalAuto 77.6% 9.7% 9.7% 97.0% PHV to Medium Truck 1.6% 0.2% 0.2% 2.0% ADT factorHeavy Truck 0.8% 0.1% 0.1% 1.0% 10%

80.0% 10.0% 10.0% 100.0%
FUTURE NO PROJECT CONDITIONS Distance to Distance to Site Roadway Edge of Centerline, Speed Traffic Volume PHV to Barrier Adjust., 24-Hour Roadway Segment Width*, ft Roadway, ft feet mph PHV ADT ADT factor Atten. dBA CNEL Alton Parkway
- West of Ranch Pkwy 100 20 70 50 1,358 13,580 10% 0 0 68.4- Between Ranch Pkwy and Town Centre Dr 100 20 70 50 1,277 12,770 10% 0 0 68.1 - Between Towne Centre Dr and Portola Pkwy 90 20 65 50 868 8,680 10% 0 0 66.7- East of Portola Pkwy 70 20 55 50 361 3,610 10% 0 0 63.7 Bake Parkway
- West of Towne Centre Dr 80 20 60 45 1,042 10,420 10% 0 0 66.5 - Between Towne Centre Dr and Portola Pkwy 80 20 60 45 1,297 12,970 10% 0 0 67.5- East of Portola Pkwy 80 20 60 45 1,261 12,610 10% 0 0 67.4 Ranch Parkway
- North of Alton Pkwy 80 20 60 45 208 2,080 10% 0 0 59.5- South of Alton Pkway 80 20 60 45 227 2,270 10% 0 0 59.9 Towne Centre Drive
- Between Alton Pkwy and Bake Pkwy 80 25 65 35 839 8,390 10% 0 0 62.3 Portola Parkway
- North of Alton Pkwy 100 20 70 45 369 3,690 10% 0 0 61.4- Between Alton Pkwy and Bake Pkwy 100 20 70 45 1,337 13,370 10% 0 0 67.0 - South of Bake Pkwy 100 20 70 45 1,733 17,330 10% 0 0 68.1 * Estimated based on Google Earth map.** Calculated using FHWA's TNM Version 2.5 Computer Noise Model.

Date Printed: 11/21/2025
1997
A E S
Acoustical Engineering Services
Off-Site Traffic Noise CalculationsProject: Costco Foothill Ranch Project Traffic Distribution as % of ADT
Vehicle Type Day Eve Night Sub totalAuto 77.6% 9.7% 9.7% 97.0% PHV to Medium Truck 1.6% 0.2% 0.2% 2.0% ADT factorHeavy Truck 0.8% 0.1% 0.1% 1.0% 10%

80.0% 10.0% 10.0% 100.0%
FUTURE + PROJECT CONDITIONS Distance to Distance to Site Roadway Edge of Centerline, Speed Traffic Volume PHV to Barrier Adjust., 24-Hour Roadway Segment Width*, ft Roadway, ft feet mph PHV ADT ADT factor Atten. dBA CNEL Alton Parkway
- West of Ranch Pkwy 100 20 70 50 1,582 15,820 10% 0 0 69.0- Between Ranch Pkwy and Town Centre Dr 100 20 70 50 1,622 16,220 10% 0 0 69.2 - Between Towne Centre Dr and Portola Pkwy 90 20 65 50 931 9,310 10% 0 0 67.0- East of Portola Pkwy 70 20 55 50 392 3,920 10% 0 0 64.1 Bake Parkway
- West of Towne Centre Dr 80 20 60 45 1,336 13,360 10% 0 0 67.6 - Between Towne Centre Dr and Portola Pkwy 80 20 60 45 1,367 13,670 10% 0 0 67.7- East of Portola Pkwy 80 20 60 45 1,555 15,550 10% 0 0 68.3 Ranch Parkway
- North of Alton Pkwy 80 20 60 45 208 2,080 10% 0 0 59.5- South of Alton Pkway 80 20 60 45 249 2,490 10% 0 0 60.3 Towne Centre Drive
- Between Alton Pkwy and Bake Pkwy 80 25 65 35 1,491 14,910 10% 0 0 64.8 Portola Parkway
- North of Alton Pkwy 100 20 70 45 401 4,010 10% 0 0 61.8- Between Alton Pkwy and Bake Pkwy 100 20 70 45 1,337 13,370 10% 0 0 67.0 - South of Bake Pkwy 100 20 70 45 1,962 19,620 10% 0 0 68.7 * Estimated based on Google Earth map.** Calculated using FHWA's TNM Version 2.5 Computer Noise Model.

Date Printed: 11/21/2025
1998
Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix I
Appendix I – TIS Technical Memo
Item: 11
1999
Kittelson & Associates, Inc.

Technical Memorandum
November 26, 2025 (Updated January 21, 2026) Project# 31380 To: Connor Musler, Tran Tran, & Dennis Jue – City of Lake Forest Scott Ma – City of Lake Forest Consultant Traffic Engineer From: Kristine Connolly, Fernando Sotelo, PE, Dhruv Nair, & Sam Godon CC: Mike Okuma & Therese Garcia, Costco Wholesale
RE: Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc. (Kittelson) has prepared this Focused Transportation Impact Study (TIS) for the proposed Costco warehouse at 22602 Towne Centre Drive in the Foothill Ranch Towne Centre in Lake Forest, California. This TIS examines the existing transportation network and addresses the transportation impacts associated with the proposed development of the Costco warehouse facility in Lake Forest, California.

The results of this TIS indicate that the proposed Costco Wholesale Warehouse can be developed while maintaining acceptable traffic operations at all study intersections. The project is estimated to result in a net decrease of 4,737 miles to total regional daily vehicle miles traveled. The methodology of our analysis, pertinent findings and our recommendations are documented herein.

Introduction

PROJECT DESCRIPTION
Costco Wholesale is proposing to develop a new Costco warehouse at the site of the former Regal Cinemas movie theater located at 22602 Towne Center Drive in the Foothill Ranch Towne Centre in Lake Forest, California. The proposed warehouse is anticipated to be 165,068 square feet and open by 2028.

Figure 1 presents the location of the project and Figure 2 presents the project site plan. 851 SW 6th Avenue, Suite 600
Portland, OR 97204
P 503.228.5230
Item: 11
2000
241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
N H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 15, 2025 - 11:36am - dnair Layout Tab: Site Vicinity Map Site Vicinity Map
Lake Forest, CA 1
Foothill Ranch Costco November 2025
Figure
405
55 241
39 73 5
5 74 1
91 90
57 ORANGE

SITE COUNTY
Item: 11
2001
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Jan 21, 2026 - 6:02pm - dnair Layout Tab: Proposed Site Plan Proposed Site Plan Lake Forest, California 2 Foothill Ranch Costco Revised January 2026 Figure RECEIVED FROM MG2 : (January 21 2026) 2002
November 2025 Page 4
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

SCOPE OF STUDY
Kittelson coordinated a TIS scope, methodology, and key assumptions with the City of Lake Forest in June 2025. The TIS was prepared in accordance with agency feedback on the approved scoping memorandum dated June 4th 2025. Appendix A includes the scoping memorandum and correspondence.

Per guidance from the city this study evaluates traffic operations for the following scenarios during the Weekday PM and Saturday Midday Peak Hours:
 Existing Conditions
 Existing with Project Conditions
 Opening Year without Project Conditions
 Opening Year with Project Conditions
Study intersections were selected for traffic operations analysis based on proposed trip distribution criteria of receiving 50 or more site trips during the weekday PM peak hour, per scoping conversations with City staff. All the study intersections are signalized. CA-241/Alton Parkway (intersection 1) and CA241/Portola Parkway (intersection 15) are maintained by CalTrans, while the remaining intersections are maintained by the City of Lake Forest. Study intersections are listed below:

1. CA-241 / Alton Parkway

2. Alton Parkway / Towne Centre Drive

3. Alton Parkway / Portola Parkway

4. Market Place / Towne Centre Drive

5. Market Place / Portola Parkway

6. Entertainment / Towne Centre Drive

7. Bake Parkway / Town Centre Drive

8. Bake Parkway / Portola Parkway

9. Lake Forest Drive / Town Centre Drive

10. Lake Forest Drive / Portola Parkway

11. Town Centre Drive / Portola Parkway

12. Glenn Ranch Road / Portola Parkway

13. Commercentre Drive / Alton Parkway

14. Rancho Parkway S / Alton Parkway

15. CA-241 / Portola Parkway

16. Rancho Parkway / Portola Parkway

17. El Toro Road / Portola Parkway

ANALYSIS METHODOLOGY
The following sections describe the analysis methodology used to assess traffic operations at each of the study intersections. At intersections maintained and operated by the City of Lake Forest (intersections 2- 14, 16, and 17), Intersection Capacity Utilization (ICU) methodology was used to assess intersection Levelof-Service (LOS). Methodology from the Highway Capacity Manual (HCM), 7th Edition was used to assess both intersection operations at Caltrans maintained and operated intersections (intersections 1 and 15) and turn pocket queuing at select locations identified by staff at the City of Lake Forest. Per City guidance, HCM methodology would also apply to unsignalized intersections maintained and operated by the City of Lake Forest, however all intersections in this study are signalized. All analyses were performed using PTV Vistro 2024 software. Per the California Environmental Quality Act (CEQA) guidelines, a VMT analysis was conducted to assess transportation impacts and is included following the Traffic Impact Analysis section of this memo.

Item: 11
2003
November 2025 Page 5
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

ICU Methodology
The intersection capacity utilization (ICU) technique is intended for signalized intersection analysis and estimates the volume-to-capacity relationship (v/c ratio) for an intersection based on the individual v/c ratios for key conflicting traffic movements. The ICU value translates to an LOS grade. Descriptions of the LOS letter grades for signalized intersections and the relationships between the various v/c ratios are provided in Table 1. To determine the LOS at the signalized intersections per City requirements, the ICU calculations used a lane capacity of 1,700 vehicles per hour per lane and intersection lost time is 0.05.

Table 1: ICU Level of Service and ICU Rating Table
LOS v/c Ratio
A 0.00–0.60
B 0.60–0.70
C 0.70–0.80
D 0.80–0.90
E 0.90–1.00
F Over 1.00
Notes: ICU methodology apply to study signalized intersections in the City of Lake Forest Source: Orange County – Congestion Management Program (2021) HCM Methodology
The HCM procedure calculates a weighted average stop delay in seconds per vehicle at a signalized and all-way stop-controlled intersections (AWSC) and assigns a level of service designation based on the delay. At two-way stop-controlled intersections (TWSC), LOS is defined for each minor-street approach, as opposed to the intersection as a whole (given that major-street through vehicular traffic experiences zero delay). At locations where the HCM methodology was applied, existing signal timing based on current plans were used1. Pedestrian and bicycle crossing volumes were identified based on traffic count data collected at each study intersection. Table 2 presents the relationship of average delay to level of service for signalized and unsignalized intersections. Note that all study intersections are signalized.

Table 2: Intersections HCM Level of Service Definitions LOS
Average Delay Per Vehicle (Seconds)
Signal TWSC/AWSC
A ≤10.0 ≤10.0
B >10.0 and ≤20.0 >10.0 and ≤15.0
C >20.0 and ≤35.0 >15.0 and ≤25.0
D >35.0 and ≤55.0 >25.0 and ≤35.0
E >55.0 and ≤80.0 >35.0 and ≤50.0
F >80.0 >50.0
Notes: HCM methodology apply to study Caltrans intersections, and 95th percentile queuing estimates Source: Highway Capacity Manual, 7th Edition
1 Signal timing for study signalized intersections were obtained from the City of Lake Forest and Caltrans.

Item: 11
2004
November 2025 Page 6
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Non-CEQA Traffic Impact Significance Criteria
According to City guidance, if an intersection exceeds LOS D under With Project conditions, the following criteria must be applied to assess whether the proposed project contributes to the deficiency and to determine if feasible roadway improvements should be identified to enhance intersection performance:
 The intersection operates at LOS D or better under Without Project conditions, but the addition of site-generated trips results in an unacceptable LOS (E or F); or  The intersection operates at LOS E or F under Without Project conditions, and the addition of project traffic results in an ICU increase greater than 0.01.

Existing Facilities
The Existing Facilities inventory identifies the site conditions and geometric characteristics of the study intersections as well as vehicular, pedestrian, bicycle and transit facilities near the project site. The Existing Conditions operations analysis is included in the Traffic Impact Analysis section of this report.

Adjacent Land Use
The site is located in the Foothill Ranch neighborhood of the City of Lake Forest, California. Specifically, the site is within the Foothill Ranch Towne Centre commercial shopping center and is designated MixedUse 43 (MU-43) zoning, which allows for a mixture of commercial, office, and residential uses. Foothill Ranch Towne Centre is home to several existing department stores, supermarkets, restaurants, and other uses. Of note, the building which was formerly the site of a Regal Cinemas movie theater will be removed from the site prior to opening of the Foothill Ranch Costco.

Roadway Network
Foothill Ranch is a neighborhood in the City of Lake Forest and is served by various transportation facilities, including one regional freeway, an extensive roadway network, off- and on-street active transportation facilities, and a bus transit line. The roadway system in the study area consists of several roadway functional classification categories as categorized in the City of Lake Forest General Plan Mobility Element (Reference 1). The five classifications are Principle Arterial, Major Arterial, Primary Arterial, Secondary Arterial, and Collector. It is assumed that city roadways not identified in the General Plan’s roadway classification map are locally classified roadways. The Caltrans facilities included in this study are classified based on their state functional roadway classifications. The roadway classifications and the existing roadway network characteristics are listed in Table 3. The existing lane configurations and traffic control devices at the 17 study intersections are provided in Figure 3.

Item: 11
2005
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 9:05am - dnair Layout Tab: 3_ELC & TCD Existing Lane Configurations &
Traffic Control Devices
Lake Forest, CA 3
Foothill Ranch Costco November 2025
Figure
## - Study Intersections
- Stop Sign
- Traffic Signal
- Channelizing Island / Pedestrian Refuge Island
- Existing Lane Configuration
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy
Item: 11
2006
November 2025 Page 8
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Table 3: Existing Roadway Network Characteristics
Roadway Classification
Number
of
Lanes
Median Type
Posted
Speed
Limit
Sidewalk Bicycle
Lanes
Transit
Route
CA-241 Other
Freeway or
Expressway
3 NB / 3
SB
Separated/Landscaped
Median
65 None None None
Towne Centre
Dr
Local 2 NB / 2
SB
TWLTL / Raised
Median
35 Contiguous None 177
Portola Pkwy Major Arterial 3 NB / 3
SB
Raised Median 45 Contiguous None 177
Alton Pkwy Major Arterial 3 EB / 3
WB
Raised Median 50-60 Contiguous Class II None
Market Pl Local 2 EB / 2
WB
TWLTL 35 Contiguous None 177
Entertainment Private/Site
Access
1 EB / 1
WB
None 25 North Side:

Contiguous
South Side:

Intermittent
None None
Bake Pkwy Primary
Arterial
2 EB / 2
WB
Raised Median 45 Contiguous Class II 177
Lake Forest Dr Primary
Arterial
2 EB / 2
WB
Raised Median 45 Contiguous Class II 177
Glenn Ranch
Rd
Primary
Arterial
2 EB / 2
WB
Striped 55 Contiguous Class II None
Rancho Pkwy Primary
Arterial
2 EB / 2
WB
Raised Median 45 Contiguous Class II 177
El Toro Rd Major Arterial 3 EB / 3
WB
Raised Median 55 Contiguous Class I 89
Commercentre
Dr
Secondary
Arterial
2 NB / 2
SB
TWLTL 45 Contiguous None None
Where NB = northbound, SB = southbound, EB = eastbound, WB = westbound, and TWLTL = two-way left-turn lane Item: 11
2007
November 2025 Page 9
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

PEDESTRIAN FACILITIES
The study area offers several types of facilities and amenities to support walking. The availability and quality of pedestrian facilities can be analyzed using several key factors as detailed below:
 Sidewalk Availability: The abutting streets to the site contain sidewalks on both sides. However, on roadways within the Foothill Ranch Towne Centre site typically only have sidewalks on one side of the roadway. The availability of sidewalks on roadways within the study area is provided in Table 3.
 Crosswalk Availability and Type: Within the study area, marked crosswalks are consistently provided at signalized intersections. CA-241 on and off ramp intersections typically provide crossings perpendicular to ramp activities but not across major roads they intersect with.  Mild Grades: The study area has a mild inline to the northeast towards the Santa Ana Mountains.

There are also mild inclines/declines at highway underpasses and overpasses.  Pedestrian Amenities: Pedestrian amenities such as street furniture are limited along roadways in the study area, except for some bus stops that include covered benches and trash cans. There is also an extensive network of paved and unpaved trails for pedestrians [and bicyclists] in the Foothill Ranch area.

BICYCLE FACILITIES
Bicycle facilities are defined by the following four classes in Chapter 1000 of the Caltrans Highway Design Manual and Design Information Bulletin 89:
 Class I bikeway (bike path) – Provides a completely separated facility designed for the exclusive use of bicyclists and pedestrians with crossing points minimized.  Class II bikeway (bike lane) – Provides a restricted right-of-way lane for the exclusive or semiexclusive use of bicycles with through travel by motor vehicles or pedestrians prohibited, but with vehicle parking and cross-flows by pedestrians and motorists permitted.  Class III bikeway (bike route) – Provides a right-of-way designated by signs or permanent markings and shared with pedestrians and motorists.
 Class IV bikeway (cycle track) – This is a dedicated, separated and protected on-street lane for bicyclists. Cycle tracks (or protected bike lanes) typically are used along streets with high traffic volumes and high speeds, providing additional protection for bicyclists using vertical separation, such as concrete curbs or safe-hit posts.

Within the site vicinity bike facilities are provided along major roads [omitting highways] as identified in Table 3 and are typically Class II facilities.

TRANSIT SERVICE
Transit service near the Project site is provided by the Orange County Transportation Authority. In the Project vicinity, bus service is provided along the following routes:
 177 – Laguna Niguel to Mission Viejo via Foothill Ranch Towne Centre  89 – Laguna Beach to Rancho Santa Margarita along El Toro Rd Item: 11
2008
November 2025 Page 10
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.
 480 – Irvine Metrolink Station to Lake Forest
Traffic Impact Analysis
This section documents the following:
 Existing Conditions Analysis (2025)
 Trip Generation and Distribution Estimates for the Project  Existing with Project Conditions Analysis (2025)
 Opening Year without Project Conditions Analysis (2028)  Opening Year with Project Conditions Analysis (2028)

EXISTING CONDITIONS
Traffic Volumes
Turning movement counts were collected in May and June 2025 (with public schools in session) at the study intersections during the weekday PM peak period (4:00-6:00 PM) and Saturday Midday peak period (11:00 AM – 2:00 PM). The existing weekday PM and Saturday midday peak hour volumes are shown in Figures 4 and 5, respectively. Appendix B contains the Traffic counts.

Item: 11
2009
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 11:44am - dnair Layout Tab: 4_EX_WK Existing Traffic Volumes
Weekday PM Peak Hour
Lake Forest, CA 4
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N 7464
3 210 116 14
160
399
56 2
328
24 153 816 183 64916 1274
181
141 174
123
34 73 106543 221209
4 8
3 172 125
25 78 74 599 290 74789 73777
28 72 236
26 430 522 151
1197
316 18
746 1732795 114 1815
154
1025
99 34
550
29 187 8240
0925 208
134
0 224 79
0 129 468 818
3 901053
6 147
15 838 1
11 3 56
045 112
0247
168
744
0 51
454
0 275 47728 24680 16277
50 140 56
33 104 1864612 314542134
686
198 43
371
40 43 302
3 35300
7 25
3 47 2
1 1 344 186 139 45187
0 75
112
520 105
53 3 105 15352 287 154 52
238
659
106 46
519
87 12593 115 26180 130
33 95
73 87
193
86 242 57966 91612 349
108
366
214 125
225
184 375 98142 340 1276 258
222
401
492 16
188
108
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy
Item: 11
2010
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 03, 2025 - 10:38am - dnair Layout Tab: 5_EX_SAT Existing Traffic Volumes
Saturday Midday Peak Hour
Lake Forest, CA 5
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N 1835
4 114 63
3 176
227
27 1
305
31 134 742 131 75731 651
86 92 91
89 12 63 98115 13884
8 13
5 92 19
10 11 55 566 206 49507 43561
17 40 130
29 433 18150
613
149 23
613 731535 741410
66 561
52 20
443
16 155 7360
0647 105
77 0
167 74
0 113 344 705
5 68728 12
85 13
481 5
12 16 37
061 93
0152
61 503
0 49
441
0 291 33042 30387 10266
64 139 59
45 64 2033921 273321111
401
242 55
322
14 67 348
1 42304 10
32 4
60 1
0 3 257 129 102 68101
1 43
71 273 93
69 3 56 15353 317 118 29
290
422
78 47
553
75 17886 119 56175 147
60 137
96 84
230
92 286 53128 116 530 140
97 106
138 90
231
115 325 73739 237 880 161
187
284
371 9
246
143
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy
Item: 11
2011
November 2025 Page 13
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Intersection Operations
The weekday PM and Saturday midday peak-hour turning-movement volumes in Figures 4 and 5 were used to conduct an operational and queuing analysis at the study intersections to determine existing traffic conditions.

ICU ANALYSIS RESULTS
Table 4 presents the year 2025 existing traffic conditions in the weekday PM and Saturday midday peak hours. The analysis was performed using PTV Vistro 2024 software and ICU analysis methodology. The results indicate that all study intersections operate within the city’s LOS standards in the existing condition. Appendix C contains the Vistro ICU reports for Existing Traffic Conditions.

Table 4: Intersection Operations ICU Analysis Results – Existing Conditions # Intersection
Weekday PM Peak
Hour
Saturday Midday
Peak Hour
V/C1 LOS2 V/C1 LOS2
1 CA-241 / Alton Parkway 0.33 A 0.23 A
2 Alton Parkway / Towne Centre Drive 0.29 A 0.26 A
3 Alton Parkway / Portola Parkway 0.30 A 0.23 A
4 Market Place / Towne Centre Drive 0.29 A 0.35 A
5 Market Place / Portola Parkway 0.41 A 0.34 A
6 Entertainment / Towne Centre Drive 0.19 A 0.22 A
7 Bake Parkway / Towne Centre Drive 0.53 A 0.54 A
8 Bake Parkway / Portola Parkway 0.53 A 0.42 A
9 Lake Forest Drive / Towne Centre Drive 0.37 A 0.28 A
10 Lake Forest Drive / Portola Parkway 0.48 A 0.35 A
11 Towne Centre Drive / Portola Parkway 0.45 A 0.31 A
12 Glenn Ranch Road / Portola Parkway 0.55 A 0.35 A
13 Alton Parkway / Commercentre Drive 0.51 A 0.27 A
14 Alton Parkway / Rancho Parkway South 0.44 A 0.26 A
15 CA-241 / Portola Parkway 0.39 A 0.29 A
16 Portola Parkway / Rancho Parkway (Purpose Drive) 0.44 A 0.33 A 17 Portola Parkway (Santa Margarita Parkway) / El Toro Road 0.51 A 0.42 A 1Volume-to-capacity ratio
2Level of Service
Item: 11
2012
November 2025 Page 14
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

HCM ANALYSIS RESULTS
Table 5 presents existing traffic conditions in the weekday PM and Saturday midday peak hours following HCM 7th edition methodology. As indicated, both intersections operate at a LOS “B” during both peak hour periods. Appendix D contains Vistro HCM reports for Existing Traffic Conditions.

Table 5. Intersection Operations HCM Analysis Results – Existing Conditions # Intersection
Weekday PM Peak Hour Saturday Midday Peak Hour
Delay (seconds) LOS1 Delay (Seconds) LOS1
1 CA-241 / Alton Parkway 18.0 B 13.7 B
15 CA-241 / Portola Parkway 19.4 B 17.1 B
1Level of Service
Queuing Operations
Queuing behaviors were analyzed at the left-turn and right-turn pockets of select study intersections identified by staff at the City of Lake Forest. Additionally, queuing was analyzed at the two intersections operated and maintained by Caltrans along CA-241. Queuing analysis was performed using PTV Vistro 2024 software and HCM 7th Edition analysis methodology to obtain 95th percentile queue lengths. The 95th percentile queue lengths in the year 2025 existing conditions are reported in Table 6. Appendix D contains Vistro HCM reports for Existing Traffic Conditions.

There are three movements for which the 95th percentile queue length exceeds the available turn pocket storage under existing conditions, indicated by the bold text in the table:
 The eastbound left-turn at CA-241 / Alton Parkway (intersection 1)  The southbound left-turn at Portola Parkway / Market Place (intersection 5)  The northbound left-turn at Towne Centre Drive / Bake Parkway (intersection 7) Item: 11
2013
November 2025 Page 15
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Table 6. 95th Percentile Queue Lengths - Existing Conditions # Intersection Movement Available Storage (feet)
95th Percentile Queue Length (ft)1,2
Year 2025 Existing Conditions
Weekday PM Peak
Hour
Saturday Midday
Peak Hour
1 CA-241 / Alton Pkwy*
NBL 410 50 25
SBL >500 150 100
EBL 165 225 100
WBL 410 75 75
2 Towne Centre Dr /
Alton Pkwy
NBL 300 125 75
NBR 180 25 25
SBL 150 75 25
SBR 150 25 25
EBL 350 175 75
WBL 150 75 50
4 Towne Centre Dr /
Market Pl
NBL 180 25 50
SBL 185 25 50
EBL 100 25 25
WBL 175 25 25
5 Portola Pkwy /
Market Pl
NBL 375 225 250
SBL 205 275 200
EBL 205 150 125
WBL3 100 100 100
6 Towne Centre Dr /
Entertainment
NBL 150 25 25
SBL 150 25 25
SBR 170 25 25
EBL 100 25 25
WBL3 25 25 25
7 Towne Centre Dr /
Bake Pkwy
NBL 155 175 100
SBL 245 100 50
EBL 290 200 200
WBL 155 50 50
15 CA-241/Portola Pkwy
NBL >500 75 50
SBL 500 75 25
EBL >500 75 50
WBL >500 25 25
1 Reported queues rounded to nearest vehicle length assuming 25 feet per vehicle. 2Bolded queue lengths exceed the available storage length 3Parking lot approach, additional storage available if needed.

Item: 11
2014
November 2025 Page 16
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

PROPOSED PROJECT
Costco Wholesale is proposing to develop a new Costco warehouse at the site of the former Regal Cinemas movie theater located at 22602 Towne Center Drive in the Foothill Ranch Towne Centre in Lake Forest, California. The proposed warehouse is anticipated to be 165,068 square feet and open by 2028.

The site plan is shown in Figure 2. The following section describes the trip generation and distribution associated with the proposed Costco Warehouse site and the impacts of those trips on the study intersections.

Trip Generation

COSTCO TRIP DATABASE
For more than 25 years, Kittelson has maintained a database of traffic data and travel characteristics for Costco Wholesale. The database contains transportation information such as trip rates, trip type percentages, and parking demand for Costco locations throughout the United States as well as Canada and Mexico. The database is updated periodically each time new Costco traffic counts or other information become available to Kittelson.

To best evaluate the anticipated characteristics of the proposed Foothill Ranch Costco warehouse, the Costco database was used to develop the trip generation estimate since it provides use-specific data that most accurately represents the anticipated traffic characteristics of the unique development type. Because of members-only access requirement and the nature of Costco sales, Costco members have unique travel characteristics and patterns, which are different from customers of other retail facilities. The Costcospecific trip generation data presented herein follows nationally accepted practices for trip generation data collection as recommended by the Institute of Transportation Engineers (ITE).

While many Costco warehouse sites within the Costco trip database contain locations that include fuel facilities and the gas trips are inherently included in the overall trip generation for the Costco development, this memorandum and trip generation has been specifically tailored to present the anticipated trip generation characteristics of a Costco warehouse located within California that does not provide a fuel facility at its location.

FOOTHILL RANCH COSTCO TRIP CHARACTERISTICS
Table 7 summarizes the trip generation characteristics and rates recorded at four representative Costco warehouse sites without fuel facilities located in California. These Costco warehouse sites (two located in the Los Angeles metro area and two located in the San Francisco metro area) are a refined sample of representative locations as they are located within California provide a Costco warehouse with no fuel facility, as is proposed at the Foothill Ranch location.

Costco warehouses open at 9 AM for Executive Members and 10 AM for all other members on weekdays.

As such, they do not generate significant traffic during the typical commuter weekday AM peak period.

The Foothill Ranch Costco will not have a fuel facility, so a very nominal number of trips are expected to be generated during the weekday AM peak hour (only a minimal number of employees and deliveries). In Item: 11
2015
November 2025 Page 17
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.
addition to analyzing the traditional weekday PM peak hour, the Saturday midday data is offered in this case because Costco warehouses typically experience the highest customer volumes during the weekend Saturday midday peak.

Table 7 also summarizes the percentage of pass-by, diverted and primary trips recorded at three of the four representative sites during the weekday PM peak hour and Saturday midday peak hour based on trip characteristic data calculated from member surveys taken at the three locations. Appendix E includes a trip generation summary for the representative Costco warehouse sites.  Pass-by trips include existing trips that are on roadways adjacent to the site that allow the motorist to turn into the Costco development, and then continue to their ultimate destination when their shopping is concluded;
 Diverted trips include existing trips on nearby roadways on which the motorist decides to drive out-of-direction for a distance to stop at Costco, and when their shopping is concluded, continue on their trip to the ultimate destination; and,
 Primary trips include an entirely new trip on the roadway system for the express purpose of driving to and from Costco, after deducting pass-by and diverted trips.

Table 7. Average Trip Characteristics for a Costco Warehouse without Fuel Facility Land Use/Trip Type Weekday
Daily Trip
Rate
(per KSF)
Weekday PM Peak Hour Saturday Midday Peak Hour
Trip Rate
(per KSF)
Portion
In
Portion
Out
Trip Rate
(per KSF)
Portion
In
Portion
Out
Costco Warehouse without
Fuel Facility

73.19 6.42 44% 56% 8.99 51% 49%
Diverted/Pass-by Trips1 36%2 36% 18%3
Primary Trips 64%2 64% 82%3
Source: Kittelson & Associates, Inc. (2025)
1Due to the location of the proposed Costco, limited pass-by trips are anticipated from adjacent roadways. Instead, these trips were accounted for as diverted trips from CA-241. The diverted/Pass-by rates in Table 7 were calculated as the combined average diverted and pass-by rates recorded at the representative sites. 2Weekday daily diverted and primary trip rates are based on the weekday PM Peak Hour. 3Saturday midday diverted and primary trip rates recorded at the representative sites were approximately half of the weekday PM peak hour rates. This difference is likely attributed to more chained trips occurring during the weekday work commute.

The trip rates in Table 7 represent the total external trips recorded at the four representative sites.

However, it is anticipated that a portion of the trips associated with the Foothill Ranch Costco will be made by people who are already visiting other retail and restaurant uses within the Foothill Ranch Town Centre and will choose to visit Costco during the same trip. To estimate the number of trips internally captured within the Foothill Ranch Towne Centre, peak hour trip internalization rates were calculated based on guidance in the ITE Trip Generation Handbook, 3rd Edition (Reference 2) and daily trip internalization rates were developed based on guidance in the ITE Trip Generation Handbook, 2nd Edition (Reference 3). Consistent with ITE best practices, internal trips are subtracted from the total trips before diverted and pass-by rates are applied to the remaining external trips.

Item: 11
2016
November 2025 Page 18
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

FOOTHILL RANCH COSTCO TRIP GENERATION ESTIMATE
Based on the trip data and characteristics summarized in the section above, Table 8 presents trip generation estimates for the proposed Foothill Ranch Costco warehouse using internal capture information in the ITE Trip Generation Handbook and the average data shown in Table 7.

Table 8. Foothill Ranch Costco Warehouse Trip Generation Estimate Land Use/Trip Type Size Weekday
Daily
Weekday PM Peak
Hour
Saturday Midday Peak
Hour
Total In Out Total In Out
Costco Warehouse Total Trip Ends 165,068
SF
12,081 1,060 477 583 1,484 757 727
Internal Trips Ends (28% weekday
daily, 13.2% weekday PM, 12.1%
Sat midday)
(3,382) (138) (74) (64) (179) (95) (84)
Total External Trip Ends 8,699 922 403 519 1,305 662 643 Diverted Trip Ends (36% weekday
daily, 36% weekday PM, 18% Sat
midday)
(3,132) (332) (166) (166) (234) (117) (117)
Primary Trip Ends 5,567 590 237 353 1,071 545 526
Project Trip Distribution
The distribution of site-generated trips onto the roadway system within the study area considers existing population and demographic data as well as the location of existing Costco members who currently shop at other Costco locations but are likely to shift their shopping to the Foothill Ranch Costco, as it will be closer and more convenient. The site trip distribution accounts for the fact that CA-241 is a toll road with variable pricing throughout the day, which may influence travel patterns to and from the proposed site.

INTERNAL TRIPS
Shared trips with other retail and restaurant uses within the Foothill Ranch Town Centre would remain internal to the Towne Centre and would not impact the study intersections.

DIVERTED TRIPS
Diverted trips to the site would be from CA-241. While treated as new trips at the CA-241 interchange and proposed site accesses, diverted trips result in fewer system capacity and environmental impacts as compared to new trips to the system because these trips generally have no impact once traced back onto the system they divert from. The following peak hour directional distribution for diverted trips was assumed:
• 50% westbound and 50% eastbound during the weekday PM peak hour • 50% westbound and 50% eastbound during the Saturday midday peak hour Item: 11
2017
November 2025 Page 19
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

The origin of the diverted trips was also considered when forecasting where vehicles would enter and exit CA-241. For diverted trips, the following distribution was assumed for traffic along CA-241:
 75% of westbound diverted trips would exit CA-241 using Portola Parkway  25% of westbound diverted trips would exit CA-241 using Alton Parkway  100% of eastbound diverted trips would exit CA-241 using Alton Parkway  100% of westbound diverted trips would enter CA-241 using Alton Parkway  75% of eastbound diverted trips would exit CA-241 using Portola Parkway  25% of eastbound diverted trips would exit CA-241 using Alton Parkway The diverted trip assignment and distribution for the weekday PM and Saturday PM peak hour are shown in Figures 6 and 7.

PRIMARY TRIPS
The Costco warehouse primary trip distribution was developed based on a market study prepared by Costco and review of local travel patterns within the vicinity of the proposed development. Based on this assessment, primary site trips will distribute to the study intersections according to the following distribution:
 3% to/from the north via Alton Parkway
 6% to/from the north via Bake Parkway
 7% to/from the north via Glenn Ranch Road
 30% to/from the east via CA-241
 8% to/from the south via Portola Parkway
 8% to/from the south via Lake Forest Drive
 8% to/from the south via Bake Parkway
 7% to/from the south via Alton Parkway
 20% to/from the west via CA-241
 3% to/from the west via Portola Parkway
The primary trip assignment and distribution for the weekday PM and Saturday PM peak hour is shown in Figures 8 and 9.

TOTAL EXTERNAL SITE-GENERATED TRIPS
The total volume of external site-generated trips was obtained by adding together the primary site trips and diverted site trips. The total site-generated trip assignment for the weekday PM and Saturday PM peak hour is show in Figures 10 and 11.

Costco Warehouse Hours of Operation
Costco warehouse retail facilities are open to members only and operate seven days a week. On weekdays, standard hours are 10:00 AM to 8:30 PM, with Executive Members permitted to begin shopping at 9:00 AM. Weekend operating hours open to members are typically from 9:30 or 10:00 AM to 6:00 PM.

The warehouses are typically closed on major holidays.

Item: 11
2018
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 15, 2025 - 11:57am - dnair Layout Tab: 6_WK_TG_Divert Diverted Trip Assignment
Weekday PM Peak Hour
Lake Forest, CA 6
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 21 83
21 83 104
104 3152 7826
52 15 3131 2615
52 47 37 3725
25 25
25 37 37 25 25 3725 25
37 62 6262
62 Item: 11
2019
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 15, 2025 - 11:50am - dnair Layout Tab: 7_SAT_TG_Divert Diverted Trip Assignment
Saturday Midday Peak Hour
Lake Forest, CA 7
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 15 58
14 59 73
73 2237 5518
36 11 2222 1811
37 33 26 2618
18 18
18 26 26 18 18 2618 18
26 44 4444
44 Item: 11
2020
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 15, 2025 - 11:59am - dnair Layout Tab: 8_WK_TG_Primary Primary Trip Assignment
Weekday PM Peak Hour
Lake Forest, CA 8
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 12
55 80
18 9822
67 14
7 11
11 7 7860 6120
60 58 7878 2058
60 175 83 25123 85
17 56 42
21 64
14 64 2895
19 42 64 6442 64
95 89 134 25
17 5
36 7
52 5
50 7
73 65 9935
24 65 99 56 1485
9 Item: 11
2021
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 15, 2025 - 11:51am - dnair Layout Tab: 9_SAT_TG_Primary Primary Trip Assignment
Saturday Midday Peak Hour
Lake Forest, CA 9
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 27
125 121
26 14731
152 32 16
16 15 16 18089 138 46
89 87 181 180 4687
89 261 192 37184 127
38 131 98
32 95
33 148 42142
44 98 95 14898 95
142 208 200 37
38 11
81 10
79 11114
11 110 153 147 53
55 153 147 131 21126
22 Item: 11
2022
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 03, 2025 - 11:25am - dnair Layout Tab: 10_WK_TG_tot Total Site-Generated Trip Assignment
Weekday PM Peak Hour
Lake Forest, CA 10
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 21 95
55 21
80 101 20222
171 14
7 11
11 7 109 112 139 46
112
73 109 109 4673
112
222 120 25160 110
17 81 67
21 89
14 101 28132
19 67 89 10167 89
132 151 196 25
17 5
36 7
52 5
50 7
73 65 9997
86 65 99 56 1485
9 Item: 11
2023
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 03, 2025 - 11:27am - dnair Layout Tab: 11_SAT_TG_tot Total Site-Generated Trip Assignment
Saturday Midday Peak Hour
Lake Forest, CA 11
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 15 85
125
14 121
85 22031
225 32 16
16 15 16 202 126 193 64
125
98 203 202 6498
126
294 218 37210 145
38 149 116
32 113
33 174 42168
44 116 113 174 116 113
168 252 244 37
38 11
81 10
79 11114
11 110 153 147 97
99 153 147 131 21126
22 Item: 11
2024
Revised January 2026 Page 26
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Truck Deliveries and Circulation
The warehouse truck loading docks are located at the northwest corner of the site, as shown in the proposed site plan in Figure 2. Delivery trucks are expected to approach from Bake Parkway, turn left onto Portola Parkway, and then turn left onto Towne Centre Drive to access the site via the Towne Centre Drive/Market Place intersection. Trucks will circulate behind the Costco building toward the loading docks and exit the site via the same intersection, traveling north toward Portola Parkway before returning to Bake Parkway. Tire deliveries associated with the future Tire Center are expected to occur after normal operating hours to minimize on-site conflicts and customer interaction. Detailed truck circulation patterns, turning movements, and path-of-travel diagrams will be provided in the architectural site plans.

EXISTING WITH PROJECT CONDITIONS
The effects of the project on existing traffic operations at the study intersections are discussed in this section as a means of analyzing the impact of site generated traffic on the study intersections.

Intersection Operations
The total site generated trips were added to Existing Conditions volumes to develop traffic volumes for Existing with Project conditions. The existing with project weekday PM and Saturday midday peak hour volumes are shown in Figure 12 and 13, respectively.

ICU ANALYSIS RESULTS
Table 9 presents the existing with project traffic operations at the study intersections. The results indicate that all study intersections are projected to operate within LOS standards. Appendix F contains Vistro ICU reports for Existing with Project Traffic Conditions.

Item: 11
2025
November 2025 Page 27
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Table 9. Intersection Operations ICU Analysis Results – Existing with project Conditions # Intersection
Weekday PM Peak
Hour
Saturday Midday
Peak Hour
V/C1 LOS2 V/C1 LOS2
1 CA-241 / Alton Parkway 0.37 A 0.29 A
2 Alton Parkway / Towne Centre Drive 0.36 A 0.33 A
3 Alton Parkway / Portola Parkway 0.30 A 0.24 A
4 Market Place / Towne Centre Drive 0.47 A 0.62 B
5 Market Place / Portola Parkway 0.41 A 0.34 A
6 Entertainment / Towne Centre Drive 0.41 A 0.54 A
7 Bake Parkway / Towne Centre Drive 0.57 A 0.62 B
8 Bake Parkway / Portola Parkway 0.55 A 0.46 A
9 Lake Forest Drive / Towne Centre Drive 0.40 A 0.36 A
10 Lake Forest Drive / Portola Parkway 0.50 A 0.38 A
11 Towne Centre Drive / Portola Parkway 0.58 A 0.48 A
12 Glenn Ranch Road / Portola Parkway 0.56 A 0.40 A
13 Alton Parkway / Commercentre Drive 0.52 A 0.29 A
14 Alton Parkway / Rancho Parkway South 0.45 A 0.29 A
15 CA-241 / Portola Parkway 0.42 A 0.35 A
16 Portola Parkway / Rancho Parkway (Purpose Drive) 0.46 A 0.36 A 17 Portola Parkway (Santa Margarita Parkway) / El Toro Road 0.53 A 0.45 A 1Volume-to-capacity ratio
2Level of Service
Item: 11
2026
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 7:29am - dnair Layout Tab: 12_EX_WK_wProj Existing with Project Traffic Volumes
Weekday PM Peak Hour
Lake Forest, CA 12
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 5666 112 342
168
799
0 72
534
0 3884634 314542134
686
369 57
371
40 344 186 139 5218786
123
520 105
60 3 234 205 115 165 226 130145
95 146 87
193
86 275 47728 24680 16277
50 140 56
33 104 152 411
3 81373
7 137
3 269 2
1 1 105 27352 312 314 162255
659
106 46
519
168 309 57966 91612 349108
387
303 125
239
184 74 165
3 238 248 14
179
399
56 2
328
24 153 883 183 641005 1274
181
141 174
123
34 174 113243 221298
4 8
3 304 125
25 78 74 750 290 74985 76277
28 72 236
26 447 522 156
1233
316 25
798 17327 100 114 1815
154
1075
99 41
623
29 187 889
0 01024 305
134
224 79
215 468 883
3 901152
6 147
15 838 1
11 3 375 103742 354 1361 258231
401
492 16
188
108
0 0
0 0
Item: 11
2027
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 7:40am - dnair Layout Tab: 13_EX_SAT_wProj Existing with Project Traffic Volumes
Saturday Midday Peak Hour
Lake Forest, CA 13
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 3776 93237
61 628
0 63
562
0 4233952 273321111
401
467 87
322
14 257 129 102 84101
1 59
86 273 93
85 3 380 212 119 249 239 147185
137
194 84
230
92 291 33042 30387 10266
64 139 59
45 64 270 550
1 106 402 10
158
4 354 1
3 56 37153 354 328 174328
422
78 47
553
224 402 53128 116 530 14097
138
251 90
264
115 18 209
4 156 231
3 220
227
27 1
305
31 134 858 131 75844
6 51
86 92 91
89 12 237 109715 13997
8 13
5 260 19
10 11 55 818 206 49751 47261
17 40 130
29 471 18161
694
149 33
692 731546 741410
66 675
52 31
553
16 147 889
0 0794 202
77 167 70
186 344 858
5 68875 12
85 13
481 5
12 16 325 86839 258 1006 161209
284
371 9
246
143
0 0
0 0
0 Item: 11
2028
November 2025 Page 30
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

HCM ANALYSIS RESULTS
Table 10 presents the existing with project traffic conditions in the weekday PM and Saturday midday peak hours following HCM 7th edition methodology. With the additional traffic from the proposed development, there is no change in LOS when compared to existing conditions at both intersections during both peak hours. Appendix G contains HCM reports for Existing with Project Traffic Conditions.

Table 10. Intersection Operations HCM Analysis Results – Existing with Project Conditions # Intersection
Weekday PM Peak Hour Saturday Midday Peak Hour
Delay (seconds) LOS1 Delay (Seconds) LOS1
1 CA-241 / Alton Parkway 19.9 B 15.4 B
15 CA-241 / Portola Parkway 19.9 B 17.8 B
1Level of Service
Queuing Operations
Queuing behaviors were analyzed at the left-turn and right-turn pockets of select study intersections identified by staff at the City of Lake Forest. Additionally, queuing was analyzed at the two intersections operated and maintained by Caltrans along CA-241. Queuing analysis was performed using PTV Vistro 2024 software and HCM 7th Edition analysis methodology to obtain 95th percentile queue lengths. The 95th percentile queue lengths in the year 2025 existing with project conditions are reported in Table 11.

Appendix G contains HCM reports for Existing with Project Traffic Conditions.

The three movements exceeding available turn pocket storage under existing conditions continue to exceed storage under existing with project conditions, indicated by the bold text in the table:
 The eastbound left-turn at CA-241 / Alton Parkway (intersection 1)  The southbound left-turn at Portola Parkway / Market Place (intersection 5)  The northbound left-turn at Towne Centre Drive / Bake Parkway (intersection 7) The project does not contribute trips to these movements, and the 95th percentile queues are not increased by the project compared to existing conditions.

Item: 11
2029
November 2025 Page 31
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Table 11. 95th Percentile Queue Lengths – Existing with Project Conditions # Intersection Movement Available Storage (feet)
95th Percentile Queue Length (ft)1,2
Year 2025 Existing with Project
Weekday PM
Peak Hour
Saturday Midday
Peak Hour
1 CA-241 / Alton Pkwy*
NBL 410 50 25
SBL >500 200 150
EBL 165 225 100
WBL 410 100 100
2 Towne Centre Dr / Alton
Pkwy
NBL 300 300 125
NBR 180 50 25
SBL 150 75 25
SBR 150 25 25
EBL 350 175 75
WBL 150 75 75
4 Towne Centre Dr /
Market Pl
NBL 180 75 150
SBL 185 50 50
EBL 100 75 100
WBL 175 50 50
5 Portola Pkwy / Market Pl
NBL 375 225 250
SBL 205 275 200
EBL 205 150 125
WBL3 100 100 100
6 Towne Centre Dr /
Entertainment
NBL 150 75 125
SBL 150 25 25
SBR 170 25 50
EBL 100 50 75
WBL3 25 25 25
7 Towne Centre Dr / Bake
Pkwy
NBL 155 175 100
SBL 250 250 125
EBL 290 200 225
WBL 155 50 50
15 CA-241/Portola Pkwy
NBL >500 75 50
SBL 500 125 75
EBL >500 100 50
WBL >500 25 25
1 Reported queues rounded to nearest vehicle length assuming 25 feet per vehicle. 2Bolded queue lengths exceed the available storage length 3Parking lot approach, additional storage available if needed.

Item: 11
2030
November 2025 Page 32
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.

Based on the conditions described above, no modifications to the existing turn lane storage are recommended at these locations.

OPENING YEAR (2028) WITHOUT PROJECT CONDITIONS
This section describes volumes and operations associated with the future year 2028 traffic conditions in absence of the project at each of the study intersections.

Background Growth
Based on direction from the staff at the City of Lake Forest, a 2% compound annual growth rate was applied to existing turning movement counts to account for general growth within the study area.

In-Process Developments
The City has confirmed the following previously approved or pending developments to include in the traffic forecasts for the year 2028. The trips associated with the “in-process” development traffic can be found in Appendix H.
19712 PAULING IMI PROJECT
This approved development includes 27,324 square feet of manufacturing, 7,840 square feet of warehouse and 19,848 square feet of office. The traffic analysis completed for the development assigned trips to Portola Parkway/Towne Centre Drive (intersection 11). These trips were carried through the remaining study intersections based on existing traffic patterns. The traffic analysis did not provide a Saturday peak hour analysis. No Saturday midday peak hour trips were assumed as this development includes only industrial and office uses.

NAKASE PROJECT
This approved development includes 675 single-family homes, 101 senior affordable housing units, a 1,000-student elementary school and additional park space. Per the City, the majority of the development has been completed and 57 remaining single-family homes are under construction. A proportion of remaining trips, relative to the total development trips, was calculated and assigned to the study intersections based on the trip distribution provided in the traffic analysis completed for the development.

Where the traffic analysis did not provide trip assignment, trips were carried through the remaining study intersections based on existing traffic patterns. The traffic analysis did not provide a Saturday peak hour analysis. Saturday midday peak hour volumes were conservatively assumed to be equal to the PM peak hour volumes.

PORTOLA CENTER
This approved development includes 613 single family homes, 260 multi-family homes, 57 affordable multi-family homes, and 10,000 square feet of neighborhood-serving commercial space. Per the City, the majority of the development has been completed and 123 remaining single-family homes are under construction. A proportion of remaining trips, relative to the total development trips, was calculated and Item: 11
2031
November 2025 Page 33
Foothill Ranch Costco Focused Transportation Impact Study Kittelson & Associates, Inc.
assigned to the study intersections based on the trip distribution provided in the traffic analysis completed for the development. Where the traffic analysis did not provide trip assignment, trips were carried through the remaining study intersections based on existing traffic patterns. The traffic analysis did not provide a Saturday peak hour analysis. Saturday midday peak hour volumes were conservatively assumed to be equal to the PM peak hour volumes.

WESTERN REALCO ENTERPRISE WAY INDUSTRIAL PROJECTS
This approved development includes two buildings which consist of 78,202 square feet of manufacturing, 60,598 square feet of warehouse and 18,000 square feet of office. The traffic analysis completed for the development did not assign any trips to the study intersection for the Proposed Foothill Ranch Costco.

Thus, the trips from this development were carried through the study intersections using engineering judgement. The traffic analysis did not provide a Saturday peak hour analysis. No Saturday midday peak hour trips were assumed as this development includes only industrial and office uses.

IPT ENTERPRISE BUSINESS CENTER LLC PROJECT
This approved development includes two buildings which consist of approximately 65,000 square feet of manufacturing, 89,000 square feet of warehouse and 10,000 square feet of office. The traffic analysis completed for the development did not assign any trips to the study intersections for the Proposed Foothill Ranch Costco. Thus, the trips from this development were carried through the study intersections using engineering judgement. The traffic analysis did not provide a Saturday peak hour analysis. No Saturday midday peak hour trips were assumed as this development includes only industrial and office uses.

Planned Transportation Improvements
There are no funded changes to the study intersections and/or streets within the next three years that will materially affect traffic volumes.

Intersection Operations
2028 Opening Year without project traffic volumes include traffic attributed to a compound annual growth rate of 2.0% applied to existing traffic volumes and additional trips from in-process developments.

The year 2028 opening year without project weekday PM and Saturday midday peak hour volumes are shown in Figures 14 and 15, respectively.

Item: 11
2032
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 7:37am - dnair Layout Tab: 14_28_WK_NoProj 2028 without Project Traffic Volumes
Weekday PM Peak Hour
Lake Forest, CA 14
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 5949 119 263
178
794
0 54
485
0 1974912 334846142
733
211 45
399
44 371 199 149 4820179
119
558 112
56 3 13499 122 27192 13835
102
79 92
210
91 297 51532 25732 17282
53 150 61
35 111 46 321
3 38320
7 27
3 51 2
1 1 111 16256 307 164 55254
703
114 49
558
92 262 62972 98661 371115
388
230 136
240
195 8368
3 223 125 15
170
443
61 2
359
26 168 888 197 68990 1378
201
161 188
136
36 79 115053 231314
5 8
3 185 159
29 94 79 640 327 79848 83083
33 76 262
28 481 570 160
1277
339 19
797 18529 101 121 1916
163
1092
108 36
587
31 198 896
0 01002 223
142
238 85
138 501 891
3 971135
7 157
16 892 1
12 3 399 105045 369 1363 275251
428
522 17
203
115
0 0
0 0
Item: 11
2033
1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 7:40am - dnair Layout Tab: 15_28_SAT_NoProj 2028 without Project Traffic Volumes
Saturday Midday Peak Hour
Lake Forest, CA 15
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 3966 99162
65 538
0 52
470
0 2154122 293523118
431
258 59
345
16 277 138 109 72109
1 46
75 296 100
73 3 19091 126 60187 15664
146
103 89
247
98 312 35646 32420 10870
68 148 65
48 68 71 370
1 45325 11
34 4
65 1
3 59 16256 339 126 31309
452
84 50
592
80 307 57431 124 573 148104
112
149 99
246
122 2137
4 121 69
3 187
244
29 1
326
33 143 801 140 80793
6 54
92 99 100
95 12 69 105716 14960
8 14
5 101 23
11 11 58 601 237 52538 49065
21 43 150
31 478 19253
658
159 24
655 791637 791511
70 599
59 21
472
17 156 800
0 0699 111
82 177 75
92 369 768
5 73784 14
91 14
513 5
13 17 346 78941 259 938 171212
303
394 9
264
152
0 0
0 0
0 Item: 11
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ICU ANALYSIS RESULTS
Table 12 presents the opening year without project traffic operations at the study intersections. The results indicate that all study intersections are projected to operate within mobility standards. Appendix I includes Vistro reports for Opening Year without Project Traffic Conditions.

Table 12. Intersection Operations ICU Analysis Results – Opening Year without Project Conditions # Intersection
Weekday PM Peak
Hour
Saturday Midday
Peak Hour
V/C1 LOS2 V/C1 LOS2
1 CA-241 / Alton Parkway 0.35 A 0.25 A
2 Alton Parkway / Towne Centre Drive 0.31 A 0.27 A
3 Alton Parkway / Portola Parkway 0.32 A 0.24 A
4 Market Place / Towne Centre Drive 0.31 A 0.37 A
5 Market Place / Portola Parkway 0.44 A 0.36 A
6 Entertainment / Towne Centre Drive 0.20 A 0.23 A
7 Bake Parkway / Towne Centre Drive 0.56 A 0.57 A
8 Bake Parkway / Portola Parkway 0.57 A 0.45 A
9 Lake Forest Drive / Towne Centre Drive 0.39 A 0.29 A
10 Lake Forest Drive / Portola Parkway 0.52 A 0.38 A
11 Towne Centre Drive / Portola Parkway 0.49 A 0.33 A
12 Glenn Ranch Road / Portola Parkway 0.60 A 0.40 A
13 Alton Parkway / Commercentre Drive 0.55 A 0.28 A
14 Alton Parkway / Rancho Parkway South 0.47 A 0.28 A
15 CA-241 / Portola Parkway 0.41 A 0.31 A
16 Portola Parkway / Rancho Parkway (Purpose Drive) 0.47 A 0.35 A 17 Portola Parkway (Santa Margarita Parkway) / El Toro Road 0.55 A 0.45 A 1Volume-to-capacity ratio
2Level of Service

HCM ANALYSIS RESULTS
Table 13 presents the opening year without project traffic conditions in the weekday PM and Saturday midday peak hours following HCM 7th edition methodology. The results indicate both intersections are projected to operate at a LOS of B without additional traffic generated by the proposed development during both the Weekday PM and Saturday Midday peak hours. Appendix J contains the Opening Year without Project Traffic conditions Vistro HCM reports.

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Table 13. Intersection Operations HCM Analysis Results – Opening Year without Project Conditions # Intersection
Weekday PM Peak Hour Saturday Midday Peak Hour
Delay (seconds) LOS1 Delay (Seconds) LOS1
1 CA-241 / Alton Parkway 18.3 B 13.8 B
15 CA-241 / Portola Parkway 19.6 B 17.5 B
1Level of Service
Queuing Operations
Queuing behaviors were analyzed at the left-turn and right-turn pockets of select study intersections identified by staff at the City of Lake Forest. Additionally, queuing was analyzed at the two intersections operated and maintained by Caltrans along CA-241. Queuing analysis was performed using PTV Vistro 2024 software and HCM 7th Edition analysis methodology to obtain 95th percentile queue lengths. The 95th percentile queue lengths in the year 2028 without project conditions are reported in Table 14. Appendix J contains the Opening Year without Project Traffic conditions Vistro HCM reports.

The three movements exceeding available turn pocket storage under existing conditions continue to exceed storage under opening year without project conditions, indicated by the bold text in the table:
 The eastbound left-turn at CA-241 / Alton Parkway (intersection 1)  The southbound left-turn at Portola Parkway / Market Place (intersection 5)  The northbound left-turn at Towne Centre Drive / Bake Parkway (intersection 7) One additional movement exceeds available turn pocket storage under opening year without project conditions:
 The westbound left-turn at Portola Parkway / Market Place (intersection 5) Item: 11
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Table 14. 95th Percentile Queue Lengths – Opening Year without Project Conditions # Intersection Movement
Available
Storage (feet)
95th Percentile Queue Length (ft)1,2
Year 2028 without Project Conditions
Weekday PM Peak
Hour
Saturday Midday Peak
Hour
1 CA-241 / Alton
Pkwy*
NBL 410 50 25
SBL >500 175 100
EBL 165 225 100
WBL 410 75 75
2 Towne Centre
Dr / Alton
Pkwy
NBL 300 125 75
NBR 180 25 25
SBL 150 75 25
SBR 150 25 25
EBL 350 200 75
WBL 150 75 50
4 Towne Centre
Dr / Market Pl
NBL 180 50 50
SBL 185 50 50
EBL 100 25 25
WBL 175 50 25
5 Portola Pkwy /
Market Pl
NBL 375 250 250
SBL 205 300 200
EBL 205 150 125
WBL3 100 125 125
6 Towne Centre
Dr /
Entertainment
NBL 150 25 25
SBL 150 25 25
SBR 170 25 25
EBL 100 25 25
WBL3 25 25 25
7 Towne Centre
Dr / Bake Pkwy
NBL 155 175 100
SBL 245 100 50
EBL 290 200 200
WBL 155 50 50
15 CA241/Portola
Pkwy
NBL >500 75 50
SBL >500 75 50
EBL >500 100 50
WBL >500 25 25
1 Reported queues rounded to nearest vehicle length assuming 25 feet per vehicle. 2Bolded queue lengths exceed the available storage length 3Parking lot approach, additional storage available if needed.

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OPENING YEAR (2028) WITH PROJECT CONDITIONS
This section describes volumes and operations associated with the future year 2028 traffic conditions with the project in place at each of the study intersections.

Intersection Operations
The 2028 Opening Year with Project Condition volumes were developed by adding the site-generated trips from the proposed project to the Opening Year (2028) without project traffic volumes. The weekday PM and Saturday midday peak hour volumes for the 2028 Opening Year with Project scenario are shown in Figures 16 and 17, respectively.

ICU ANALYSIS RESULTS
Table 15 presents the opening year with project traffic operations at the study intersections. The results indicate that all study intersections are projected to operate within acceptable LOS standards. Appendix K includes Vistro worksheets for Opening Year with Project Traffic Conditions.

Table 15. Intersection Operations ICU Analysis Results – Opening Year with Project Conditions # Intersection Weekday PM Peak
Hour
Saturday Midday
Peak Hour
V/C1 LOS2 V/C1 LOS2
1 CA-241 / Alton Parkway 0.39 A 0.30 A
2 Alton Parkway / Towne Centre Drive 0.37 A 0.34 A
3 Alton Parkway / Portola Parkway 0.32 A 0.25 A
4 Market Place / Towne Centre Drive 0.49 A 0.64 B
5 Market Place / Portola Parkway 0.44 A 0.36 A
6 Entertainment / Towne Centre Drive 0.42 A 0.55 A
7 Bake Parkway / Towne Centre Drive 0.61 B 0.65 B
8 Bake Parkway / Portola Parkway 0.59 A 0.49 A
9 Lake Forest Drive / Towne Centre Drive 0.42 A 0.38 A
10 Lake Forest Drive / Portola Parkway 0.54 A 0.40 A
11 Towne Centre Drive / Portola Parkway 0.62 B 0.50 A
12 Glenn Ranch Road / Portola Parkway 0.60 B 0.44 A
13 Alton Parkway / Commercentre Drive 0.56 A 0.30 A
14 Alton Parkway / Rancho Parkway South 0.48 A 0.30 A
15 CA-241 / Portola Parkway 0.44 A 0.37 A
16 Portola Parkway / Rancho Parkway (Purpose Drive) 0.49 A 0.38 A 17 Portola Parkway (Santa Margarita Parkway) / El Toro Road 0.57 A 0.48 A 1Volume-to-capacity ratio
2Level of Service
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1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 10:02am - dnair Layout Tab: 16_28_WK_wProj 2028 with Project Traffic Volumes
Weekday PM Peak Hour
Lake Forest, CA 16
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 5970 119 358
178
849
0 75
565
0 3994934 334846142
733
382 59
399
44 371 199 149 5520190
130
558 112
63 3 243 211 122 166 238 138147
102
152 92
210
91 297 51532 25732 17282
53 150 61
35 111 155 430
3 84393
7 139
3 273 2
1 1 111 28256 332 324 165271
703
114 49
558
173 329 62972 98661 371115
409
319 136
254
195 83 169
3 251 257 15
189
443
61 2
359
26 168 955 197 681079 1378
201
161 188
136
36 180 121753 231403
5 8
3 317 159
29 94 79 791 327 791044 85583
33 76 262
28 498 570 165
1313
339 26
849 18529 106 121 1916
163
1142
108 43
660
31 198 961
0 01101 320
142
238 85
224 501 956
3 971234
7 157
16 892 1
12 3 399 110645 383 1448 275260
428
522 17
203
115
0 0
0 0
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1 2
3 4
5 6
7 8
9 10
11 12
13 14
16 15
17 241 Alton Parkway Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
El Toro Rd
Rancho Pkwy
Commercentre Dr
Town Centre Drive
Parkway
Portola
Rancho Pkwy
SITE
17 14
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Nov 24, 2025 - 7:48am - dnair Layout Tab: 17_28_SAT_wProj 2028 with Project Traffic Volumes
Saturday Midday Peak Hour
Lake Forest, CA 17
Foothill Ranch Costco November 2025
Figure
11 12
9 10
16 13 15
1 2 3 4
6 7 8
5 N
## - Study Intersections
Towne Centre Dr Portola Pkwy Towne Centre Dr
Towne Centre Dr Towne Centre Dr Towne Centre Dr
CA-241 CA-241 Alton Pkwy
Portola Pkwy
Portola Pkwy Portola Pkwy
Portola Pkwy Portola Pkwy Portola Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Alton Pkwy Market Pl Entertainment Bake Pkwy Market Pl Bake Pkwy Lake Forest Dr Lake Forest Dr Towne Centre Dr / Pauling Glenn Ranch Rd Commercentre Dr Rancho Pkwy S
Portola Pkwy
Rancho Pkwy/Purpose Dr El Toro Rd
Portola Pkwy / Santa
Margarita Pkwy 3981 99247
65 663
0 66
591
0 4354153 293523118
431
483 91
345
16 277 138 109 88109
1 62
90 296 100
89 3 392 217 126 253 251 156189
146
201 89
247
98 312 35646 32420 10870
68 148 65
48 68 274 572
1 109 423 11
160
4 359 1
3 59 38056 376 336 176347
452
84 50
592
229 423 57431 124 573 148104
144
262 99
279
122 21 211
4 163 237
3 231
244
29 1
326
33 143 917 140 80906
6 54
92 99 100
95 12 243 117316 141073
8 14
5 269 23
11 11 58 853 237 52782 52765
21 43 150
31 516 19264
739
159 34
734 791648 791511
70 713
59 32
582
17 156 953
0 0846 208
82 177 75
191 369 921
5 73931 14
91 14
513 5
13 17 346 92041 280 1064 171234
303
394 9
264
152
0 0
0 0
0 Item: 11
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HCM ANALYSIS RESULTS
Table 16 presents the opening year with project traffic conditions in the weekday PM and Saturday midday peak hours following HCM 7th edition methodology. With the additional traffic from the proposed development, the LOS of both Caltrans’ intersections are anticipated to drop from a LOS “B” to “C” in the weekday PM peak hour and remain at a LOS of “B” in the Saturday midday peak hour. Appendix L includes the Vistro HCM reports for the Opening Year with Project traffic conditions.

Table 16. Intersection Operations HCM Analysis Results – Opening Year with Project Conditions # Intersection
Weekday PM Peak Hour Saturday Midday Peak Hour
Delay (seconds) LOS1 Delay (Seconds) LOS1
1 CA-241 / Alton Parkway 20.1 C 15.5 B
15 CA-241 / Portola Parkway 20.1 C 18.1 B
1Level of Service
Queuing Operations
Queuing behaviors were analyzed at the left-turn and right-turn pockets of select study intersections identified by staff at the City of Lake Forest. Additionally, queuing was analyzed at the two intersections operated and maintained by Caltrans along CA-241. Queuing analysis was performed using PTV Vistro 2024 software and HCM 7th Edition analysis methodology to obtain 95th percentile queue lengths. The 95th percentile queue lengths in the year 2028 with project conditions are reported in Table 17. Appendix L contains Opening Year with Project Traffic Conditions Vistro HCM reports.

The four movements exceeding available turn pocket storage under opening year without project conditions continue to exceed storage under opening year with project conditions, indicated by the bold text in the table:
 The eastbound left-turn at CA-241 / Alton Parkway (intersection 1)  The southbound left-turn at Portola Parkway / Market Place (intersection 5)  The westbound left-turn at Portola Parkway / Market Place (intersection 5)  The northbound left-turn at Towne Centre Drive / Bake Parkway (intersection 7) The project does not contribute trips to these movements, and the 95th percentile queues are not increased by the project compared to without project conditions.

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Table 17. 95th Percentile Queue Lengths – Opening Year with Project Conditions # Intersection Movement
Available
Storage (feet)
95th Percentile Queue Length (ft)1,2
Year 2028 Future with Project
Weekday PM Peak
Hour
Saturday Midday Peak
Hour
1 CA-241 / Alton
Pkwy*
NBL 410 50 25
SBL >500 225 175
EBL 165 225 100
WBL 410 100 100
2 Towne Centre
Dr / Alton
Pkwy
NBL 300 325 150
NBR 180 50 25
SBL 150 75 25
SBR 150 25 25
EBL 350 200 75
WBL 150 100 75
4 Towne Centre
Dr / Market Pl
NBL 180 75 150
SBL 185 50 50
EBL 100 75 100
WBL 175 50 50
5 Portola Pkwy /
Market Pl
NBL 375 250 250
SBL 205 300 200
EBL 205 150 125
WBL3 100 125 125
6 Towne Centre
Dr /
Entertainment
NBL 150 75 125
SBL 150 25 25
SBR 170 25 50
EBL 100 75 75
WBL3 25 25 25
7 Towne Centre
Dr / Bake Pkwy
NBL 155 175 100
SBL 250 250 250
EBL 290 200 225
WBL 155 50 50
15 CA241/Portola
Pkwy
NBL >500 75 50
SBL >500 125 75
EBL >500 100 50
WBL >500 25 25
1 Reported queues rounded to nearest vehicle length assuming 25 feet per vehicle. 2Bolded queue lengths exceed the available storage length 3Parking lot approach, additional storage available if needed.

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There is one additional location where the proposed project (i.e. existing with project condition) resulted in the 95th percentile queue exceeding the available storage:
 The northbound left-turn at Towne Centre Drive / Alton Parkway (intersection 2) o The outside lane of the dual left-turn lanes is continuous as a drop lane from the inside through lane, providing additional storage to accommodate peak hour queues.

Based on the conditions described above, no modifications to the existing turn lane storage are recommended at these locations.

Vehicle Miles Traveled Analysis
In January 2016, the California Office of Planning and Research (OPR), now the Governor's Office of Land Use and Climate Innovation (OLCI), published for public review and comment a Revised Proposal on Updates to the CEQA Guidelines on Evaluating Transportation Impacts in CEQA, recommending that transportation impacts for projects be measured using a VMT metric. In December 2018, the California Natural Resources Agency certified and adopted the CEQA Guidelines update package, including the section implementing Senate Bill (SB) 743 (section 15064.3). OPR developed a Technical Advisory on Evaluating Transportation Impacts in CEQA, which contains OPR’s technical recommendations regarding assessment of VMT, thresholds of significance, and mitigation measures.

In July 2020, the City of Lake Forest revised its CEQA Significance Thresholds Guide (Reference 4) to remain compliant with new requirements and adopted its own VMT significance thresholds for analyzing transportation impacts under CEQA, consistent with OPR’s guidance. For retail projects, this document states that a proposed project that does not result in a net increase in total VMT will be considered to have a less-than-significant impact on transportation. Per guidance from City staff, there are two acceptable methodologies for analyzing VMT for retail projects: either based on VMT per employee of based on the total project VMT accounting. For this project, the VMT analysis was conducted based on the total project VMT accounting.

This document provides an overview of the proposed methodology and preliminary results of a VMT analysis to determine the project’s potential impact on the transportation network.

VMT METHODOLOGY
The proposed VMT analysis methodology provided in this section uses proprietary Costco membership data to understand how opening a new warehouse would influence the number and length of Costco trips in the region. The City’s guidelines recommend that total VMT for retail projects be assessed using the Lake Forest Traffic Analysis Model (“LFTAM”); however, since the land use associated with this Project (members-only wholesale retail warehouse) is not easily represented in the model, an alternative methodology has been adopted using Costco-specific transaction data from nearby Costco facilities.

The project’s impact on regional VMT is comprised of the following general components:

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 Shifting Existing Member Trips – The VMT associated with existing members replacing existing warehouse trips to other Costco facilities with trips to the proposed facility.  New Member Trips – The VMT associated with existing or new members making new trips on the transportation network to visit the proposed facility.  Latent Demand Member Trips – The VMT associated with Costco members making more frequent trips to existing Costco locations due to latent demand that would occur after some members shift to the proposed facility and the existing warehouses become less busy.  Employee VMT – The VMT associated with employees traveling to/from the proposed facility.

VMT DATA
This section provides an overview of the proprietary Costco membership data, transaction data, and member trip data used in this analysis.

TRIP GENERATION
Trip generation estimates for each trip type were developed for the warehouse using trip rates from a database of proprietary Costco traffic data and travel characteristics, as mentioned previously in this document. Trip generation estimates were also developed for several nearby Costco facilities (listed below) to understand how existing trips to these facilities may shift to the proposed warehouse.  Irvine (WH #454) – 115 Technology Drive, Irvine, CA
 Tustin (WH #1001) – 2700 Park Avenue, Tustin, CA
 Tustin Ranch (WH #122) – 2655 El Camino Real, Tustin, CA  Laguna Niguel (WH #28) – 27972 Cabot Road, Laguna Nigel, CA  Laguna Marketplace (WH #690) – 27220 Heather Ridge Road, Laguna Niguel, CA Table 18 shows trip generation estimates for the proposed warehouse, as well as for existing Costco locations listed above. All existing Costco facilities listed above include on-site fuel facilities; since gasonly trips are not expected to shift from existing locations to the proposed Foothill Ranch Costco warehouse (with no fuel facility), the trip generation estimates for existing sites are based on daily transactions made at each warehouse.

As shown in the table, the proposed Foothill Ranch Costco facility is expected to generate approximately 8,699 weekday daily trips. Note that, due to its location, the proposed facility is not anticipated to attract true “pass-by” trips – these trips are instead included as “diverted” trips. This is a conservative assumption since diverted trips, unlike pass-by trips, have non-zero trip distances and will therefore result in a change to VMT.

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Table 18. Trip Generation Estimates (Weekday Daily)
Trip Type Foothill
Ranch
Irvine Tustin Tustin
Ranch
Laguna
Niguel
Laguna
Marketplace
Weekday Daily Trips 8,699 13,874 14,960 11,636 8,017 12,927 Employee Trips 600 600 600 600 600 600
Member Trips 8,099 13,274 14,360 11,036 7,417 12,327
Primary Trips 5,183 8,495 9,191 7,063 4,747 7,889
Pass-by Trips 0 2,257 2,441 1,876 1,261 2,096
Diverted Trips 2,916 2,522 2,728 2,097 1,409 2,342
Source: Kittelson & Associates, Inc. (2025)

COSTCO MEMBER / TRANSACTION DATA
To understand how Costco member VMT in the region may change with the addition of the Project, the following data regarding Costco members, market areas, and transactions were compiled.  Aggregated home locations of Costco members who shopped at an existing Costco facility in the Project area during September 2024, grouped into 1-square-mile zones (Irvine, Tustin, Tustin Ranch, Laguna Niguel, Laguna Marketplace)
 Number of visits to the existing Costco facilities in September 2024 made by members in each 1- square-mile zone, separated into warehouse-only visits, gas-only visits, and shared warehouse/gas visits. A member visit was assumed to be a shared warehouse/gas visit if transactions were made at both the warehouse and the fuel facility within a 90-minute period.

Since the proposed facility does not include a fuel facility, gas-only visits to existing locations were eliminated from the analysis.
 Market areas of the existing Costco locations and the proposed Foothill Ranch Costco.

VMT ASSESSMENT
This section presents the VMT assessment methodology and findings associated with the proposed Costco development.

PRIMARY TRIP VMT
Primary trips made by members to the proposed project site are expected to either 1) replace existing warehouse trips to the existing nearby Costco locations or 2) be new trips made on the transportation network. This section assesses VMT associated with primary warehouse trips.

Shift from Existing Costco Locations
The first component of the VMT analysis evaluates how the VMT associated with Costco members making primary trips to an existing Costco warehouse may change with the addition of a new location in Lake Forest. The new location provides another option for existing Costco members and results in lower average trip lengths for members who choose to shift their existing trip to a more convenient location.

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A spatial analysis was conducted to determine which Costco members would likely shift their existing trips and to derive the associated effect to regional VMT. ArcGIS Online software was used to calculate average trip distances to the existing Costco locations and the proposed new facility for two scenarios: without and with the new facility. The software determined the most convenient routes between each 1-squaremile zone and the existing Costcos. Average trip distances were calculated using proprietary Costco transaction data from September 2024. This analysis was then conducted assuming the presence of the new Foothill Ranch facility and assuming members would visit the Costco location most convenient to them (i.e., the one located within the shortest travel time from their homes). The following provides more details regarding the methodology and assumptions of this analysis:
 The center of each 1-square-mile zone was used for the starting/ending point of member trips (see Figure 18).
 The data provided by Costco includes information regarding warehouse-only and shared warehouse/gas visits at the existing Costco locations in September 2024. The member transactions were limited to those made by members who live within Costco’s pre-defined market areas for the five existing locations and one proposed location. This subset is used as a proxy for primary trips; transactions made by members whose homes are far from the site and were likely associated with pass-by or diverted trips (instead of primary trips beginning and ending at members’ homes) are eliminated from the dataset.
 Each transaction is assumed to correspond to two one-way trips between the members’ homes and the Costco facility (i.e., one roundtrip).
 To calculate the average primary trip lengths to the existing Costco locations, trip distances between each 1-square-mile zone and the existing facilities were determined using ArcGIS online software. Trips were routed based on minimum travel time (as opposed to shortest distance recognizing shorter distances along low-speed streets can result in longer travel times). These distances were then multiplied by the number of transactions made at facility by members within each 1-square-mile zone to calculate the total one-way miles traveled by members to each Costco location. This value divided by the average daily visits provides the average one-way trip length. Table 19 shows the average existing trip lengths for each location.  To calculate the average primary trip length when the new Foothill Ranch warehouse opens, first it was determined which existing Costco members would shift their trips to the new facility. For this analysis, it was assumed that if the travel time from a 1-square mile zone to the new location was less than the travel time to any of the existing Costco locations, all members within that zone would choose to shop at the new location. In other words, all trips currently made from that zone to an existing Costco location are assumed to shift to the new location. For zones that are closer (by travel time) to another Costco location, no shift was made, and trips by members in those zones were assumed to remain as they are today. Figure 18 shows the approximate home locations of existing Costco members whose primary warehouse trips are assumed to shift from existing Costco locations to the Foothill Ranch Costco.

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Laguna
Hills
Irvine
Costa Mesa
Santa Ana
Mission
Viejo
Laguna
Beach
Newport
Beach
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Tustin
Laguna
Niguel
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Warehouse Location Market Areas
* Grouped into one-square mile zones
Existing Costco Member Home Location*
Trips shifted to new warehouse
Trips remain at existing warehouse
Tustin Ranch
Tustin II
Laguna Niguel
Laguna Marketplace
Irvine
Tustin Ranch
Tustin II
Laguna Niguel
Laguna Marketplace
Irvine
Foothill Ranch
Figure 18. Existing Costco Membership
Locations and Member Trip Shift
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 A travel cost and preference analysis was conducted to determine whether members in select neighborhoods near the proposed Foothill Ranch Costco would continue traveling to the existing Irvine or Laguna Niguel Costco locations or shift to the new location. The analysis considered travel time and tolls along CA-241 during peak traffic periods, applying a value of time of $0.30 per minute to anticipated toll costs. Total round-trip travel costs were calculated from the onesquare-mile zones surrounding the proposed Costco to the Foothill Ranch, Irvine, and Laguna Niguel locations. Results indicated that while the Foothill Ranch Costco may provide a closer option for many members, toll costs and minimal time savings would lead some members to continue shopping at the Irvine and Laguna Niguel locations.  Note that the number of daily transactions presented in Table 19 does not equate to daily trip generation. This part of the analysis was conducted to understand the percentage of trips expected to shift from each existing location, as well as the average trip distance with and without the proposed facility.

Table 19 provides the average primary warehouse trip distances for the existing and Project conditions for each warehouse, as well as the portion of existing primary warehouse trips expected to shift from each warehouse. Table 20 shows how these values are used in combination with the trip generation estimates presented in Table 18 and Table 19 to determine how the shifting of primary warehouse trips affects regional VMT.

Table 19. Average Primary Warehouse Trip Distances - Existing vs. Proposed Costco
Location
Existing Proposed
(After new location opens)
Daily
Transactions
Total OneWay
Distance
(vehicle
miles)
Average
One-Way
Trip
Distance
Daily
Transactions
Total OneWay
Distance
(vehicle
miles)
Average
One-Way
Trip
Distance
Foothill
Ranch 0 0 0.00 2,878 11,800 4.10
Irvine 5,286 31,276 5.92 3,754 19,698 5.25
Tustin 5,285 28,041 5.31 5,135 25,513 4.97
Tustin Ranch 5,392 25,053 4.28 5,216 20,400 3.91
Laguna
Niguel 3,573 19,339 5.41 2,984 13,442 4.50
Laguna
Marketplace 5,422 21,981 4.05 4,991 18,105 3.63
Total 24,958 123,690 - 24,958 108,958 -
Source: Kittelson & Associates, Inc. (2025)
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Table 20. Primary Warehouse VMT - Shifting Existing Trips from Nearby Costco Locations Scenario / Location Primary Warehouse
Trip Length
Primary Warehouse
Trips
Primary Warehouse
Trip VMT
Existing Conditions 5.00 37,385 186,955
Irvine 5.92 8,495 50,290
Tustin 5.31 9,191 48,804
Tustin Ranch 4.28 7,063 30,230
Laguna Niguel 5.41 4,747 25,681
Laguna Marketplace 4.05 7,889 31,950
Future Conditions 4.41 37,385 164,859
Foothill Ranch 4.10 4,364 17,892
Irvine 5.25 6,033 31,673
Tustin 4.97 8,930 44,382
Tustin Ranch 3.91 6,832 26,713
Laguna Niguel 4.50 3,964 17,838
Laguna Marketplace 3.63 7,262 26,361
Change in Regional VMT -22,096
Source: Kittelson & Associates, Inc. (2025)
As shown in Table 20, the opening of the new Foothill Ranch Costco warehouse is expected to result in 4,364 daily existing primary warehouse trips to nearby Costco locations to shift to the new facility. This shift will result in a decrease in regional VMT of 22,096 miles.

New Primary Warehouse Trips
As shown in Table 20, 4,364 of the estimated 5,183 primary warehouse trips are expected to shift from the nearby Costco locations. The remaining 819 trips are assumed to be new trips on the network, made by existing or new members who previously would not have made a trip to a Costco location.

Table 21 presents the VMT associated with new primary warehouse trips. Assuming a trip length of 4.10 (developed through the previous analysis and presented in Tables 19 and 20), new primary warehouse trips are expected to generate approximately 3,358 daily vehicle miles.

Table 21. Primary Warehouse Trip VMT - New Trips
Primary Warehouse Trip Length New Primary Warehouse Trips New Primary Warehouse Trip VMT

4.10 819 +3,358
Source: Kittelson & Associates, Inc. (2025)

DIVERTED TRIP VMT
The Project is expected to generate 2,916 daily diverted warehouse trips, which are assumed to originate from CA-241. Since none of the existing nearby Costco locations are located in close proximity to CA-241, Item: 11
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none of the proposed diverted trips are expected to shift from existing Costco locations. Instead, all 2,916 daily diverted trips are assumed to be new diverted trips on the network.

As shown in Table 22, new diverted warehouse trips are expected to generate approximately 1,545 daily vehicle miles. The diverted trip length was calculated by averaging the distance traveled from the freeway off-ramp to the Costco facility for CA-241 WB and CA-241 EB.

Table 22. Diverted Warehouse Trip VMT
Diverted Warehouse Trip Length New Diverted Warehouse Trips Diverted Warehouse Trip VMT

0.53 2,916 +1,545
Source: Kittelson & Associates, Inc. (2025)

EMPLOYEE TRIP VMT
Employee Trip VMT was estimated using the 2021 Orange County VMT per employee of 24.1, provided by the Orange County Transportation Authority (Reference 5). This VMT rate was multiplied by the estimated number of employees for the new facility (300) to calculate total daily employee VMT. As presented in Table 23, the expected daily employee VMT for the new Costco facility 7,230 miles.

Table 23. Employee Trip VMT
Employees Orange County VMT per
Employee
Employee Trip VMT
300 24.1 +7,230
Source: Kittelson & Associates, Inc. (2025)

LATENT DEMAND VMT
The existing nearby Costco locations are expected to become less crowded with the opening of the new warehouse in Lake Forest after some existing members shift their trips to the new warehouse. As Costco has observed at other warehouses when a new location opens in the same market area, this latent demand could result in an increase in trip frequency to existing warehouses by existing members who continue to shop at their same warehouse. To estimate the number of additional trips expected at the existing Costco warehouses, Costco transaction data from representative warehouses in California were analyzed.

The analysis demonstrated that existing members tend to purchase more products at existing warehouses (increased sales) after a new warehouse is opened, but the increase in visit frequency (trips) to the existing warehouse is relatively minor. Table 24 shows the average annual change in member trip frequency (4.53%) at three California Costco warehouse locations after another warehouse opened in the same market area. As shown in the table, the existing Costco warehouse locations see an average of 1.5 additional trips per member per year as a result of latent demand.

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Table 24. Change in Member Frequency Associated with New Warehouse Opening Costco Location New Costco Opening Average Annual Visit Frequency (Trips per Year) Before After Change % Change
Visalia New Hanford 34.5 35.5 1 2.90%
Garden Grove Huntington Beach 44 45.5 1.5 3.41%
South Sacramento Elk Grove 27.5 29.5 2 7.27%
Average 1.5 4.53%
Source: Kittelson & Associates, Inc. (2025)
The proposed Foothill Ranch Costco is expected to become a more convenient option for Costco members visiting nearby sites, particularly those who currently shop at the Irvine, Laguna Niguel, and Laguna Marketplace locations. For the remaining two warehouses (Tustin and Tustin Ranch), some members who currently frequent these sites may find the proposed site more convenient, but the percentage of current members expected to shift to Foothill Ranch are relatively low (less than 4% each).

Since the increase in member frequency as a result of latent demand is not expected to exceed the number of trips shifting to the new warehouse (i.e. result in a net increase in total trips), this analysis assumes latent demand percentages for these two warehouses equal to the percentage expected to shift to the new location. This is a conservative assumption, since it assumes that all trips shifting from Tustin and Tustin Ranch to the Foothill Ranch warehouse will be replaced by latent demand trips.

Table 25 presents the change in VMT associated with an increase in trip frequency to the existing warehouses after a new warehouse opens (i.e. latent demand trips). As shown in the table, daily regional VMT is expected to increase by 5,225 miles.

Table 25. Latent Demand VMT
Warehouse Primary Trips Diverted Trips Total
Frequency
Added
Trips
Added
Trip
Length
VMT Frequency
Added
Trips
Added
Trip
Length

VMT VMT
Irvine 4.53% 273 5.25 1,433 4.53% 216 0.53 114 1,547
Tustin 1.94% 167 4.97 830 1.88% 94 0.53 50 880
Tustin Ranch 2.26% 148 3.91 579 2.19% 83 0.53 44 623
Laguna
Niguel

4.53% 180 4.50 810 4.53% 121 0.53 64 874
Laguna
Marketplace

4.53% 329 3.63 1,194 4.53% 201 0.53 107 1,301
Total - - - 4,846 - - - 379 +5,225
Source: Kittelson & Associates, Inc. (2025)
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CHANGE IN REGIONAL TOTAL VMT
Table 26 presents the change in regional daily VMT associated with the new Costco facility. The change in total regional daily VMT is calculated by comparing the existing VMT by Costco members in the Project area and VMT by members and employees after the new facility is opened. As presented in the table, the change in total regional daily VMT with the new facility is estimated to be a net decrease of 4,737 miles.

Table 26. Change in Regional Total VMT
Trip Type Change in Regional Daily VMT
Primary Warehouse Trips -18,738
Shifted from Existing Costco Locations -22,096
New Primary Warehouse Trips +3,358
Diverted Warehouse Trips +1,545
Employee Trips +7,230
Latent Demand at Existing Costco Locations +5,225
All Trips -4,737
Source: Kittelson & Associates, Inc. (2025)
Findings and Conclusions
The results of this TIS indicate that the proposed Costco Wholesale Warehouse can be developed while maintaining acceptable traffic operations at all study intersections. The project is estimated to result in a net decrease of 4,737 miles to total regional daily vehicle miles traveled.

We trust this TIS adequately addresses the traffic impacts associated with the proposed Foothill Ranch Costco. Please contact us if you have any questions or comments regarding the contents of this report or the analyses performed.

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References

1. City of Lake Forest. General Plan, City of Lake Forest, Revised 2020.

2. Institute of Transportation Engineers. Trip Generation Manual, 3rd Edition. 2014.

3. Institute of Transportation Engineers. Trip Generation Handbook, 2nd Edition. 2004.

4. City of Lake Forest. CEQA Significance Thresholds Guide, City of Lake Forest, Revised, 2020.

5. County of Orange. Transportation Implementation Manual, 1994.

Appendices
A. Scoping Memorandum and Correspondence with City of Lake Forest B. Traffic Counts
C. Existing ICU Worksheets
D. Existing HCM and Queue Worksheets
E. Costco Trip Generation Summary
F. Existing with Project ICU Worksheets
G. Existing with Project HCM and Queue Worksheets
H. In-Process Developments
I. Opening Year (2028) without Project ICU Worksheets
J. Opening Year (2028) without Project HCM and Queue Worksheets K. Opening Year (2028) with Project ICU Worksheets
L. Opening Year (2028) with Project HCM and Queue Worksheets Item: 11
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Appendix A – Scoping Memorandum and
Correspondence with City of Lake Forest
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TECHNICAL MEMORANDUM
April 14, 2025 Project# 31380
To: Connor Musler, Tran Tran, & Dennis Jue – City of Lake Forest Scott Ma – City of Lake Forest Consultant Traffic Engineer CC: Mike Okuma & Therese Garcia, Costco Wholesale
From: Kristine Connolly, Dhruv Nair, & Andrew McIntyre
Project: Foothill Ranch Costco
Subject: Proposed Scope of Work
Kittelson & Associates, Inc. (Kittelson) prepared this memorandum to outline the scope and assumptions of a Focused Traffic Impact Study (TIS) and California Environmental Quality Act (CEQA) Vehicle Miles Traveled (VMT) Analysis for the proposed Costco warehouse at 22602 Towne Center Drive in the Foothill Ranch Towne Centre in Lake Forest, California.

This memorandum covers the following transportation elements:
• Proposed Development Plan
• Focused Traffic Impact Study Scope
o Project Trip Generation
o Preliminary Trip Distribution
o Proposed Study Methodology
• CEQA Vehicle Miles Traveled Analysis Scope
o VMT Methodology
o VMT Data
o VMT Assessment
Please review this material and provide us with any feedback.

Proposed Development Plan
Costco Wholesale is proposing to develop a new Costco warehouse at the site of the former Regal/Cinemark movie theater located at 22602 Towne Center Drive in the Foothill Ranch Towne Centre in Lake Forest, California. The proposed warehouse is anticipated to be up to 158,000 square feet and open by 2028. Appendix “A” includes a preliminary site plan concept. 851 SW 6th Avenue, Suite 600
Portland, OR 97204
P 503.228.5230
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Focused Traffic Impact Study Scope
Kittelson is preparing a TIS to meet the requirements of the City of Lake Forest (City). The TIS will follow the requirements identified in Traffic Impact Study Requirements that are part of the City of Lake Forest’s (City) CEQA Significance Thresholds Guide (Reference 1).

PROJECT TRIP GENERATION
For more than 25 years, Kittelson has maintained a database of traffic data and travel characteristics for Costco Wholesale. The database contains transportation information such as trip rates, trip type percentages, and parking demand for Costco locations throughout the United States as well as Canada and Mexico. The database is updated periodically each time new Costco traffic counts or other information become available to Kittelson.

To best evaluate the anticipated characteristics of the proposed Foothill Ranch Costco warehouse, the Costco database was used to develop the trip generation estimate since it provides use-specific data that most accurately represents the anticipated traffic characteristics of the unique development type. Because of members-only access requirement and the nature of Costco sales, Costco members have unique travel characteristics and patterns, which are different from customers of other retail facilities. The Costcospecific trip generation data presented herein follows nationally accepted practices for trip generation data collection as recommended by the Institute of Transportation Engineers (ITE).

While many Costco warehouse sites within the Costco trip database contain locations that include fuel facilities and the gas trips are inherently included in the overall trip generation for the Costco development, this memorandum and trip generation has been specifically tailored to present the anticipated trip generation characteristics of a Costco warehouse located within California that does not provide a fuel facility at its location.

COSTCO WHOLESALE TRIP GENERATION CHARACTERISTICS
Table 1 summarizes the trip generation characteristics and rates recorded at three representative Costco warehouse sites without fuel facilities located in California. These Costco warehouse sites (one located in the Los Angeles metro area and two located in the San Francisco metro area) are a refined sample of representative locations as they are located within California provide a Costco warehouse with no fuel facility, as is proposed at the Foothill Ranch location.

Costco warehouses do not open for members until 10 AM. As such, they do not generate significant traffic during the typical commuter weekday AM peak period. The Foothill Ranch Costco will not have a fuel facility, so a very nominal number of trips are expected to be generated during the weekday AM peak hour (only a minimal number of employees and deliveries). In addition to analyzing the traditional weekday PM peak hour, the Saturday midday data is offered in this case because Costco warehouses typically experience the highest customer volumes during the weekend Saturday midday peak.

Table 1 also summarizes the percentage of pass-by, diverted and primary trips recorded at the representative sites during the weekday PM peak hour and Saturday midday peak hour based on trip Item: 11
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characteristic data calculated from member surveys taken at the three locations. Appendix “B” includes a trip generation summary for the representative Costco warehouse sites. • Pass-by trips include existing trips that are on roadways adjacent to the site that allow the motorist to turn into the Costco development, and then continue to their ultimate destination when their shopping is concluded;
• Diverted trips include existing trips on nearby roadways in which the motorist decides to drive out-of-direction for a distance to stop at Costco, and when their shopping is concluded, continue on their trip to the ultimate destination; and,
• Primary trips include an entirely new trip on the roadway system for the express purpose of driving to and from Costco, after deducting pass-by and diverted trips.

Due to the location of the proposed Costco, limited pass-by trips are anticipated from adjacent roadways.

Instead, these trips will be accounted for as diverted trips from CA-241.

Table 1. Average Trip Characteristics for a Costco Warehouse without Fuel Facility Land Use/Trip Type
Weekday
Daily Trip
Rate
(per KSF)
Weekday PM Peak Hour
Saturday Midday Peak Hour
Trip Rate
(per KSF)
Portion
In
Portion
Out
Trip Rate
(per KSF)
Portion
In
Portion
Out
Costco Warehouse without
Fuel Facility

74.05 6.48 44% 56% 9.07 51% 49%
Diverted/Pass-by Trips 36%1 36% 18%
Primary Trips 64%1 64% 82%
Source: Kittelson & Associates, Inc. (2025)
1Weekday daily diverted and primary trip rates are based on the weekday PM Peak Hour.

FOOTHILL RANCH COSTCO TRIP GENERATION ESTIMATE
Based on the data collected at the representative Costco locations, Table 2 presents trip generation estimates for the proposed Foothill Ranch Costco warehouse using the average data shown in Table 1.

Table 2 includes an estimation of internal capture between Costco and other uses within the Foothill Ranch Town Centre. Peak hour trip internalization rates were calculated based on guidance in the ITE Trip Generation Handbook, 3rd Edition (Reference 2). Daily trip internalization rates were developed based on guidance in the ITE Trip Generation Handbook, 2nd Edition (Reference 3).

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Table 2. Foothill Ranch Costco Warehouse Trip Generation Estimate Land Use/Trip Type Size Weekday
Daily
Weekday PM Peak
Hour
Saturday Midday
Peak Hour
Total In Out Total In Out
Costco Warehouse Total Trip Ends 158 KSF 11,700 1,024 451 573 1,433 731 702 Internal Trips Ends (28% weekday daily,
13% weekday PM, 12% Sat midday)
(3,276) (134) (71) (63) (175) (93) (82)
Total External Trip Ends 8,424 890 380 510 1,258 638 620 Diverted Trip Ends (36% weekday daily,
36% weekday PM, 18% Sat midday)
(3,033) (320) (160) (160) (226) (113) (113)
Primary Trip Ends 5,391 570 220 350 1,032 525 507
Source: Kittelson & Associates, Inc. (2025)

COMPARISON TO ITE TRIP GENERATION RATES FOR DISCOUNT CLUB The use of the Costco-specific trip generation data results in a higher number of total trips at the site driveways and nearby off-site intersections when compared to the general data in the ITE Trip Generation Manual for Discount Club. By comparison, the Trip Generation Manual Discount Club data was collected at:
• unidentified retail businesses,
• in unidentified communities,
• at sites that may or may not include on-site fueling pumps, • and that are located in Alabama, Alberta (Canada), California, Connecticut, Delaware, Florida, Maryland, Massachusetts, Ohio, Oregon, Pennsylvania, and Washington.

It is our professional judgment that the Costco trip rates derived from the three existing Costco sites without fuel facilities in California are the best representatives of the expected trip generation for the proposed Foothill Ranch Costco. We therefore recommend using them to evaluate the impact of the proposed Foothill Ranch Costco on the surrounding roadway network. We also note that Costco makes a significant long-term investment in each of their development sites and, as a member-based retailer, it is in Costco’s best interest to be certain that the transportation facilities that will serve the site are appropriately designed to facilitate access for members as well as to serve the needs of the surrounding community.

PRELIMINARY TRIP DISTRIBUTION
The distribution of site-generated trips onto the roadway system within the study area will be estimated based on existing population and demographic data as well as the location of existing Costco members who currently shop at other Costco locations but who may likely shift their shopping to the Foothill Ranch Costco, as it will be closer and more convenient. This distribution pattern may be refined once existing traffic counts at the study intersections are reviewed.

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DIVERTED TRIPS
Diverted trips to the site would be from CA-241. While treated as new trips at the CA-241 interchange and proposed site accesses, diverted trips result in fewer system capacity and environmental impacts as compared to new trips to the system because these trips generally have no impact once traced back onto the system they divert from. The following peak hour directional distribution for diverted trips was assumed, and will be confirmed based on traffic counts to be collected for the TIS:
• 50% westbound and 50% eastbound during the weekday PM peak hour • 50% westbound and 50% eastbound during the Saturday midday peak hour

PRIMARY TRIPS
The Costco warehouse primary trip distribution was developed based on a market study prepared by Costco. Based on this assessment, primary site trips will distribute to the study intersections according to the following distribution, illustrated in Figure 1:
• 3% to/from the north via Alton Parkway
• 6% to/from the north via Bake Parkway
• 7% to/from the north via Glenn Ranch Road
• 30% to/from the east via CA-241
• 8% to/from the south via Portola Parkway
• 8% to/from the south via Lake Forest Drive
• 8% to/from the south via Bake Parkway
• 7% to/from the south via Alton Parkway
• 20% to/from the west via CA-241
• 3% to/from the west via Portola Parkway
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© 2025 Microsoft Corporation © 2025 Maxar ©CNES (2025) Distribution Airbus DS CA-241 Alton Parkway
Bake Parkway Glenn Ranch Road
Portola Parkway
Lake Forest Drive
SITE
Town Centre Drive
H:\31\31380 - Foothill Ranch Costco Warehouse\report\figs\31380 figs.dwg Apr 14, 2025 - 11:51am - dnair Layout Tab: Proposed Trip Distribution Preliminary Primary Trip Distribution Lake Forest, California 1 Foothill Ranch Costco April 2025 Figure N XX% - Trip Distribution Percentage 20% 30% 3%6% 7% 8% 7% 8% 3% 8% 2060
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PROPOSED STUDY METHODOLOGY
The following sections outline the proposed analysis methodology associated with conducting a TIS for the proposed Foothill Ranch Costco Warehouse.

STUDY INTERSECTIONS
The following study intersections are proposed based on the preliminary trip distribution, and represent intersections expected to receive 50 or more site trips during the weekday PM peak hour:

1. CA-241 & Alton Parkway (Traffic Signal)

2. Alton Parkway & Towne Centre Drive (Traffic Signal)

3. Alton Parkway & Portola Parkway (Traffic Signal)

4. Market Place & Towne Centre Drive (Traffic Signal)

5. Market Place & Portola Parkway (Traffic Signal)

6. Entertainment & Towne Centre Drive (Traffic Signal)

7. Bake Parkway & Town Centre Drive (Traffic Signal)

8. Bake Parkway & Portola Parkway (Traffic Signal)

9. Lake Forest Drive & Town Centre Drive (Traffic Signal)

10. Lake Forest Drive & Portola Parkway (Traffic Signal)

11. Town Centre Drive & Portola Parkway (Traffic Signal)

12. Glenn Ranch Road & Portola Parkway (Traffic Signal)

ANALYSIS SCENARIOS
• Existing Conditions (Year 2025)
• Existing Conditions with Project (Year 2025)
• Opening Year Cumulative with Project (Year 2028)

ANALYSIS PERIODS
• Weekday PM Peak Hour of Adjacent Street Traffic
• Saturday Midday Peak Hour of Generator
The weekday AM peak hour is proposed to be excluded from analysis because site trips are expected to be minimal, as the warehouse is closed during the weekday AM commuter peak hour. The weekday PM peak and Saturday midday peak hours represent the critical periods for the proposed Costco warehouse and local street system operations

BACKGROUND GROWTH RATE
To account for the general growth in the area, Kittelson proposes using a compound annual growth rate of 2.0% in the TIS.

IN-PROCESS DEVELOPMENTS
Kittelson requests that the City of Lake Forest provide a list of approved in-process developments.

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PLANNED TRANSPORTATION IMPROVEMENTS
Kittelson requests that the City of Lake Forest provide a list of planned transportation improvements impacting the proposed study intersections.

ANALYSIS TOOLS AND OPERATING STANDARDS
For signalized Intersections, intersection operational analysis will be performed following the Intersection Capacity Utilization (ICU) methodology using Vistro software. For unsignalized intersections, the Highway Capacity Manual (HCM) 7th Edition methodology will be used. The City of Lake Forest has established a minimum Level of Service (LOS) of D or better for intersections within the city (Reference 1).

TRAFFIC IMPACT SIGNIFICANCE CRITERIA
A study intersection will be considered deficient if it meets the following criteria:
• Existing traffic conditions exceed operating standard. • Existing Plus Project traffic conditions degrade the LOS beyond operating standard, and acceptable operations cannot be restored through project conditions of approval. • Cumulative traffic conditions exceed operating standard, and acceptable operations cannot be restored through existing funding, project conditions of approval, or other implementation mechanisms.

CEQA Vehicle Miles Traveled Analysis Scope
In January 2016, the California Office of Planning and Research (OPR), now the Governor's Office of Land Use and Climate Innovation (OLCI), published for public review and comment a Revised Proposal on Updates to the CEQA Guidelines on Evaluating Transportation Impacts in CEQA, recommending that transportation impacts for projects be measured using a VMT metric. In December 2018, the California Natural Resources Agency certified and adopted the CEQA Guidelines update package, including the section implementing Senate Bill (SB) 743 (section 15064.3). OPR developed a Technical Advisory on Evaluating Transportation Impacts in CEQA, which contains OPR’s technical recommendations regarding assessment of VMT, thresholds of significance, and mitigation measures.

In July 2020, the City of Lake Forest revised its “City of Lake Forest CEQA Significance Thresholds Guide” to remain compliant with new requirements and adopted its own VMT significance thresholds for analyzing transportation impacts under CEQA, consistent with OPR’s guidance. For retail projects, this document states that a proposed project that does not result in a net increase in total VMT will be considered to have a less-than-significant impact on transportation.

This document provides an overview of the proposed methodology and preliminary results of a VMT analysis to determine the project’s potential impact on the transportation network.

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VMT METHODOLOGY
The proposed VMT analysis methodology provided in this section uses proprietary Costco membership data to understand how opening a new warehouse would influence the number and length of Costco trips in the region.

The project’s impact on regional VMT is comprised of the following general components:
• Shifting Existing Member Trips – The VMT associated with existing members replacing existing warehouse trips to other Costco facilities with trips to the proposed facility. • New Member Trips – The VMT associated with existing or new members making new trips on the transportation network to visit the proposed facility. • Latent Demand Member Trips – The VMT associated with Costco members making more frequent trips to existing Costco locations due to latent demand that would occur after some members shift to the proposed facility and the existing warehouses become less busy. • Employee VMT – The VMT associated with employees traveling to/from the proposed facility.

VMT DATA
This section provides an overview of the proprietary Costco membership data, transaction data, and member trip data used in this analysis.

TRIP GENERATION
Trip generation estimates for each trip type were developed for the warehouse using trip rates from a database of proprietary Costco traffic data and travel characteristics, as mentioned previously in this document. Trip generation estimates were also developed for several nearby Costco facilities (listed below) to understand how existing trips to these facilities may shift to the proposed warehouse. • Irvine (WH #454) – 115 Technology Drive, Irvine, CA
• Tustin (WH #1001) – 2700 Park Avenue, Tustin, CA
• Tustin Ranch (WH #122) – 2655 El Camino Real, Tustin, CA • Laguna Niguel (WH #28) – 27972 Cabot Road, Laguna Nigel, CA • Laguna Marketplace (WH #690) – 27220 Heather Ridge Road, Laguna Niguel, CA Table 3 shows trip generation estimates for the proposed warehouse, as well as for existing Costco locations listed above. All existing Costco facilities listed above include on-site fuel facilities; since gasonly trips are not expected to shift from existing locations to the proposed Foothill Ranch Costco warehouse (with no fuel facility), the trip generation estimates for existing sites are based on daily transactions made at each warehouse.

As shown in the table, the proposed Foothill Ranch Costco facility is expected to generate approximately 8,424 weekday daily trips. Note that, due to its location, the proposed facility is not anticipated to attract true “pass-by” trips – these trips are instead included as “diverted” trips. This is a conservative assumption since diverted trips, unlike pass-by trips, have non-zero trip distances and will therefore result in a change to VMT.

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Table 3. Trip Generation Estimates (Weekday Daily)
Trip Type Foothill
Ranch Irvine Tustin Tustin Ranch
Laguna
Niguel
Laguna
Marketplace
Weekday Daily Trips 8,424 13,874 14,960 11,636 8,017 12,927 Employee Trips 600 600 600 600 600 600
Member Trips 7,824 13,274 14,360 11,036 7,417 12,327
Primary Trips 5,007 8,495 9,191 7,063 4,747 7,889
Pass-by Trips 0 2,257 2,441 1,876 1,261 2,096
Diverted Trips 2,817 2,522 2,728 2,097 1,409 2,342
Source: Kittelson & Associates, Inc. (2025)

COSTCO MEMBER / TRANSACTION DATA
To understand how Costco member VMT in the region may change with the addition of the Project, the following data regarding Costco members, market areas, and transactions were compiled. • Aggregated home locations of Costco members who shopped at an existing Costco facility in the Project area during September 2024, grouped into 1-square-mile zones (Irvine, Tustin, Tustin Ranch, Laguna Niguel, Laguna Marketplace)
• Number of visits to the existing Costco facilities in September 2024 made by members in each 1- square-mile zone, separated into warehouse-only visits, gas-only visits, and shared warehouse/gas visits. A member visit was assumed to be a shared warehouse/gas visit if transactions were made at both the warehouse and the fuel facility within a 90-minute period.

Since the proposed facility does not include a fuel facility, gas-only visits to existing locations were eliminated from the analysis.
• Market areas of the existing Costco locations and the proposed Foothill Ranch Costco.

VMT ASSESSMENT
This section presents the VMT assessment methodology and preliminary findings associated with the proposed Costco development.

PRIMARY TRIP VMT
Primary trips made by members to the proposed project site are expected to either 1) replace existing warehouse trips to the existing nearby Costco locations or 2) be new trips made on the transportation network. This section assesses VMT associated with primary warehouse trips.

Shift from Existing Costco Locations
The first component of the VMT analysis evaluates how the VMT associated with Costco members making primary trips to an existing Costco warehouse may change with the addition of a new location in Lake Forest. The new location provides another option for existing Costco members and results in lower average trip lengths for members who choose to shift their existing trip to a more convenient location.

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A spatial analysis was conducted to determine which Costco members would likely shift their existing trips and to derive the associated effect to regional VMT. ArcGIS Online software was used to calculate average trip distances to the existing Costco locations and the proposed new facility for two scenarios: without and with the new facility. The software determined the most convenient routes between each 1-squaremile zone and the existing Costcos. Average trip distances were calculated using proprietary Costco transaction data from September 2024. This analysis was then conducted assuming the presence of the new Foothill Ranch facility and assuming members would visit the Costco location most convenient to them (i.e., the one located within the shortest travel time from their homes). The following provides more details regarding the methodology and assumptions of this analysis:
• The center of each 1-square-mile zone was used for the starting/ending point of member trips (see Figure 2).
• The data provided by Costco includes information regarding warehouse-only and shared warehouse/gas visits at the existing Costco locations in September 2024. The member transactions were limited to those made by members who live within Costco’s pre-defined market areas for the five existing locations and one proposed location. This subset is used as a proxy for primary trips; transactions made by members whose homes are far from the site and were likely associated with pass-by or diverted trips (instead of primary trips beginning and ending at members’ homes) are eliminated from the dataset.
• Each transaction is assumed to correspond to two one-way trips between the members’ homes and the Costco facility (i.e., one roundtrip).
• To calculate the average primary trip lengths to the existing Costco locations, trip distances between each 1-square-mile zone and the existing facilities were determined using ArcGIS online software. Trips were routed based on minimum travel time (as opposed to shortest distance recognizing shorter distances along low-speed streets can result in longer travel times). These distances were then multiplied by the number of transactions made at facility by members within each 1-square-mile zone to calculate the total one-way miles traveled by members to each Costco location. This value divided by the average daily visits provides the average one-way trip length. Table 4 shows the average existing trip lengths for each location. • To calculate the average primary trip length when the new Foothill Ranch warehouse opens, first it was determined which existing Costco members would shift their trips to the new facility. For this analysis, it was assumed that if the travel time from a 1-square mile zone to the new location was less than the travel time to any of the existing Costco locations, all members within that zone would choose to shop at the new location. In other words, all trips currently made from that zone to an existing Costco location are assumed to shift to the new location. For zones that are closer (by travel time) to another Costco location, no shift was made, and trips by members in those zones were assumed to remain as they are today. Figure 2 shows the approximate home locations of existing Costco members whose primary warehouse trips are assumed to shift from existing Costco locations to the Foothill Ranch Costco.
• Note that the number of daily transactions presented in Table 4 does not equate to daily trip generation. This part of the analysis was conducted to understand the percentage of trips expected to shift from each existing location, as well as the average trip distance with and without the proposed facility.

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Warehouse Location Market Areas
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Trips shifted to new warehouse
Trips remain at existing warehouse
Tustin Ranch
Tustin II
Laguna Niguel
Laguna Marketplace
Irvine
Tustin Ranch
Tustin II
Laguna Niguel
Laguna Marketplace
Irvine
Foothill Ranch
Figure 2. Existing Costco Membership
Locations and Member Trip Shift
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Table 4 provides the average primary warehouse trip distances for the existing and Project conditions (4.96 miles and 4.41 miles, respectively), as well as the portion of existing primary warehouse trips expected to shift from each warehouse. Table 5 shows how these values are used in combination with the trip generation estimates presented in Table 3 and Table 4 to determine how the shifting of primary warehouse trips affects regional VMT.

Table 4. Average Primary Warehouse Trip Distances - Existing vs. Proposed Costco Location
Existing Proposed
(After new location opens)
Daily
Transactions
Total OneWay Distance
(vehicle miles)
Average
One-Way
Trip
Distance
Daily
Transactions
Total OneWay Distance
(vehicle miles)
Average
One-Way
Trip
Distance
Foothill Ranch 0 0 0.00 3,237 16,556 5.11
Irvine 5,286 31,276 5.92 3,708 19,082 5.15
Tustin 5,285 28,041 5.31 5,120 25,174 4.92
Tustin Ranch 5,392 25,053 4.28 5,197 20,042 3.86
Laguna Niguel 3,573 19,339 5.41 2,779 11,700 4.21
Laguna Marketplace 5,422 21,981 4.05 4,917 17,434 3.55
Total 24,958 123,690 4.96 24,958 109,988 4.41
Source: Kittelson & Associates, Inc. (2025)
Table 5. Primary Warehouse VMT - Shifting Existing Trips from Nearby Costco Locations Scenario / Location Primary Warehouse
Trip Length
Primary Warehouse
Trips
Primary Warehouse
Trip VMT
Existing Conditions 5.00 37,385 186,955
Irvine 5.92 8,495 50,290
Tustin 5.31 9,191 48,804
Tustin Ranch 4.28 7,063 30,230
Laguna Niguel 5.41 4,747 25,681
Laguna Marketplace 4.05 7,889 31,950
Future Conditions 4.46 37,385 166,591
Foothill Ranch 5.11 4,868 24,875
Irvine 5.15 5,959 30,689
Tustin 4.92 8,904 43,808
Tustin Ranch 3.86 6,808 26,279
Laguna Niguel 4.21 3,692 15,543
Laguna Marketplace 3.55 7,154 25,397
Change in Regional VMT -20,364
Source: Kittelson & Associates, Inc. (2025)
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As shown in Table 5, the opening of the new Foothill Ranch Costco warehouse is expected to result in 4,868 daily existing primary warehouse trips to nearby Costco locations to shift to the new facility. This shift will result in a decrease in regional VMT of 20,364 miles.

New Primary Warehouse Trips
As shown in Table 5, 4,868 of the estimated 5,007 primary warehouse trips are expected to shift from the nearby Costco locations. The remaining 139 trips are assumed to be new trips on the network, made by existing or new members who previously would not have made a trip to a Costco location.

Table 6 presents the VMT associated with new primary warehouse trips. Assuming a trip length of 5.11 (developed through the previous analysis and presented in Tables 4 and 5), new primary warehouse trips are expected to generate approximately 710 daily vehicle miles.

Table 6. Primary Warehouse Trip VMT - New Trips
Primary Warehouse Trip Length New Primary Warehouse Trips New Primary Warehouse Trip VMT

5.11 139 +710
Source: Kittelson & Associates, Inc. (2025)

DIVERTED TRIP VMT
The Project is expected to generate 2,817 daily diverted warehouse trips, which are assumed to originate from CA-241. Since none of the existing nearby Costco locations are located in close proximity to CA-241, none of the proposed diverted trips are expected to shift from existing Costco locations. Instead, all 2,817 daily diverted trips are assumed to be new diverted trips on the network.

As shown in Table 7, new diverted warehouse trips are expected to generate approximately 1,493 daily vehicle miles. The diverted trip length was calculated by averaging the distance traveled from the freeway off-ramp to the Costco facility for CA-241 WB and CA-241 EB.

Table 7. Diverted Warehouse Trip VMT
Diverted Warehouse Trip Length New Diverted Warehouse Trips Diverted Warehouse Trip VMT

0.53 2,817 1,493
Source: Kittelson & Associates, Inc. (2025)

EMPLOYEE TRIP VMT
Employee Trip VMT was estimated using the 2021 Orange County VMT per employee of 24.1, provided by the Orange County Transportation Authority (Reference 4). This VMT rate was multiplied by the estimated number of employees for the new facility (300) to calculate total daily employee VMT. As presented in Table 8, the expected daily employee VMT for the new Costco facility 7,230 miles.

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Table 8. Employee Trip VMT
Employees Orange County VMT per
Employee Employee Trip VMT
300 24.1 7,230
Source: Kittelson & Associates, Inc. (2025)

LATENT DEMAND VMT
The existing nearby Costco locations are expected to become less crowded with the opening of the new warehouse in Lake Forest after some existing members shift their trips to the new warehouse. As Costco has observed at other warehouses when a new location opens in the same market area, this latent demand could result in an increase in trip frequency to existing warehouses by existing members who continue to shop at their same warehouse. To estimate the number of additional trips expected at the existing Costco warehouses, Costco transaction data from representative warehouses in California were analyzed.

The analysis demonstrated that existing members tend to purchase more products at existing warehouses (increased sales) after a new warehouse is opened, but the increase in visit frequency (trips) to the existing warehouse is relatively minor. Table 9 shows the average annual change in member trip frequency (4.5%) at three California Costco warehouse locations after another warehouse opened in the same market area.

As shown in the table, the existing Costco warehouse locations see an average of 1.5 additional trips per member per year as a result of latent demand.

Table 9. Change in Member Frequency Associated with New Warehouse Opening Costco Location New Costco Opening
Average Annual Visit Frequency (Trips per Year)
Before After Change % Change
Visalia New Hanford 34.5 35.5 1 2.90%
Garden Grove Huntington Beach 44 45.5 1.5 3.41%
South Sacramento Elk Grove 27.5 29.5 2 7.27%
Average 1.5 4.53%
Source: Kittelson & Associates, Inc. (2025)
The proposed Foothill Ranch Costco is expected to become a more convenient option for Costco members visiting nearby sites, particularly those who currently shop at the Irvine, Laguna Niguel, and Laguna Marketplace locations. For the remaining two warehouses (Tustin and Tustin Ranch), some members who currently frequent these sites may find the proposed site more convenient, but the percentage of current members expected to shift to Foothill Ranch are relatively low (less than 4% each).

Since the increase in member frequency as a result of latent demand is not expected to exceed the number of trips shifting to the new warehouse (i.e. result in a net increase in total trips), this analysis assumes latent demand percentages for these two warehouses equal to the percentage expected to shift to the new location. This is a conservative assumption, since it assumes that all trips shifting from Tustin and Tustin Ranch to the Foothill Ranch warehouse will be replaced by latent demand trips.

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Table 10 presents the change in VMT associated with an increase in trip frequency to the existing warehouses after a new warehouse opens (i.e. latent demand trips). As shown in the table, daily regional VMT is expected to increase by 5,167 miles.

Table 10. Latent Demand VMT
Warehouse
Primary Trips Diverted Trips Total
Frequency
Added
Trips
Added
Trip
Length VMT Frequency Added
Trips
Added
Trip
Length VMT VMT
Irvine 4.53% 270 5.15 1,391 4.53% 216 0.53 114 1,505
Tustin 2.07% 184 4.92 905 1.99% 103 0.53 55 960
Tustin Ranch 2.39% 163 3.86 629 2.32% 92 0.53 49 678
Laguna
Niguel 4.53% 167 4.21 703 4.53% 121 0.53 64 767
Laguna
Marketplace 4.53% 324 3.55 1,150 4.53% 201 0.53 107 1,257 Total - - - 4,778 - - - 388 +5,167
Source: Kittelson & Associates, Inc. (2025)

CHANGE IN REGIONAL TOTAL VMT
Table 11 presents the change in regional daily VMT associated with the new Costco facility. The change in total regional daily VMT is calculated by comparing the existing VMT by Costco members in the Project area and VMT by members and employees after the new facility is opened. As presented in the table, the change in total regional daily VMT with the new facility is estimated to be a net decrease of 5,764 miles.

Table 11. Change in Regional Total VMT
Trip Type Change in Regional Daily VMT
Primary Warehouse Trips -19,654
Shifted from Existing Costco Locations -20,364
New Primary Warehouse Trips +710
Diverted Warehouse Trips +1,493
Employee Trips +7,230
Latent Demand at Existing Costco Locations +5,167
All Trips -5,764
Source: Kittelson & Associates, Inc. (2025)
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Next Steps
Based on the information provided in this memorandum, we formally request the City of Lake Forest confirm the proposed scope and assumptions for a Focused Traffic Impact Study (TIS) and California Environmental Quality Act (CEQA) Vehicle Miles Traveled (VMT) Analysis for the proposed Costco warehouse at 22602 Towne Center Drive in the Foothill Ranch Towne Centre in Lake Forest, California. We also request that the City provide information regarding in-process developments and planned transportation improvements affecting the study area. We would request confirmation of the assumptions described in this memorandum by April 25, 2025. Please contact us at 503.535.7448 or [email protected] if you have questions and/or want to discuss this information.

References

1. City of Lake Forest. CEQA Significance Thresholds Guide, City of Lake Forest, Revised, 2020.

2. Institute of Transportation Engineers. Trip Generation Manual, 3rd Edition. 2014.

3. Institute of Transportation Engineers. Trip Generation Handbook, 2nd Edition. 2004.

4. County of Orange. Transportation Implementation Manual, 1994.

Appendices
Appendix A – Preliminary Site Plan
Appendix B – Trip Generation Summary
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Scoping Memo
Appendix A - Preliminary Site Plan
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Scoping Memo
Appendix B - Trip Generation Summary
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Non-Gas Warehouse Trip Generation Comparison
In Out Total Primary Pass-By Diverted In Out Total Primary Pass-by Diverted In Out Total Foster City 121.06 3.17 3.73 6.91 61% 16% 23% 5.01 4.82 9.83 78% 6% 16% 36.54 37.33 73.87 San Francisco 132.01 3.02 3.43 6.45 60% 20% 20% 4.48 4.14 8.63 88% 6% 6% 33.93 34.75 68.67 Los Feliz 149.71 2.40 3.67 6.08 71% 14% 15% 4.27 4.47 8.74 78% 13% 9% 39.32 40.28 79.59 Average 134.26 2.87 3.61 6.48 64% 17% 19% 4.59 4.48 9.07 82% 8% 10% 36.60 37.45 74.05 Location
PM Peak Hour Saturday Midday Peak Hour Daily
Size (KSF)
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MEMORANDUM
DATE: APRIL 25, 2025
TO: CONNOR MUSLER, ASSOCIATE PLANNER
CC: TRAN TRAN, TRAFFIC ENGINEERING MANAGER

DENNIS JUE, DEPUTY CITY ENGINEER
FROM: SCOTT MA, TRAFFIC ENGINEERING CONSULTANT
SUBJECT: REVIEW OF TRAFFIC STUDY SCOPE OF WORK FOR
PROPOSED FOOTHILL RANCH COSTCO AT 26602

TOWNE CENTRE DRIVE
Traffic Engineering has reviewed the Technical Memorandum for the Foothill Ranch Costco, Proposed Scope of Work (Kittleson & Associates, Inc., April 14, 2035). We have the following comments:

1. Truck-Turning Analysis – Add the truck turning analysis for the design delivery trucks to the scope of work unless that item will be addressed separately. Please advise how this item will be addressed.

2. Trip Generation (page 3) – The proposed trip generation data was based on counts taken at three (3) different Costco’s in the State of California.

However, two (2) of these were located in northern California; and the other one was located in southern California. Please collect and use trip generation data at one (1) additional location in southern California.

3. Trip Distribution and Assignment (page 5) – It notes that approximately 50 percent of the project trips will use State Route (SR) 241. It should be noted that SR 241 is a toll road/freeway with prices that vary by time of day and day of the week. The price of the toll may alter the person’s decision to shop at the proposed Foothill Ranch Costco.

As shown in the attached marked-up Exhibit, some of those that live in the highlighted areas may decide to shop at the proposed Foothill Ranch Costco; and others may decide to shop at their existing Costco rather than pay to use the toll road/freeway. Does the traffic modeling account for the toll road pricing for using SR 241?
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Memorandum – Wholesale Membership Warehouse