Noise and Vibration Analysis
Technical Report
for the
Marcos Specific Plan Project
City of San Marcos, California
Prepared for:
AOA San Marcos, LLC
709 Randolph Avenue
Costa Mesa, California 92626
Contact: Chris Bennett
Prepared by:
605 Third Street
Encinitas, California 92024
Contacts: Cole Martin, INCE; Mark Storm, INCE Bd. Cert.
JUNE 2023
Printed on 30% post-consumer recycled material.
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Table of Contents
SECTION PAGE NO.
ACRONYMS AND ABBREVIATIONS ............................................................................................................................. III 1 INTRODUCTION AND BACKGROUND ............................................................................................................. 1 2 REGULATORY SETTING ............................................................................................................................... 11 3 EXISTING CONDITIONS ................................................................................................................................ 16 4 THRESHOLDS OF SIGNIFICANCE ................................................................................................................ 18 5 IMPACT DISCUSSION .................................................................................................................................. 19 6 MITIGATION MEASURES .............................................................................................................................. 33 7 SUMMARY OF FINDINGS ............................................................................................................................. 35 8 REFERENCES CITED .................................................................................................................................... 37
FIGURES
Figure 1 Project Location ...................................................................................................................................... 5 Figure 2 Project Site .............................................................................................................................................. 7 Figure 3 Site Plan .................................................................................................................................................. 9 Figure 4 Aggregate Stationary Sources Operational Noise Level Prediction – HVAC Only ............................ 28 Figure 5 Aggregate Stationary Sources Operational Noise Level Prediction – HVAC Plus Event .................. 30 TABLES
Table 1. City of San Marcos Exterior Noise Standards ................................................................................................. 15 Table 2. December 14, 2022 Measured Outdoor Ambient Sound Environment Samples ....................................... 16 Table 3. Typical Construction Equipment Maximum Noise Levels .............................................................................. 19 Table 4. Predicted Construction Noise Levels per Activity Phase ................................................................................ 20 Table 5. Off-site Roadway Traffic Noise Modeling Results ........................................................................................... 22 Table 6. HVAC Only Stationary Operations Noise Modeling Results ........................................................................... 26 Table 7. HVAC Plus Event Stationary Operations Noise Modeling Results ................................................................. 27
APPENDICES
A. Baseline Noise Measurement Field Data (Dudek Forms)
B. Construction Noise Prediction Model Worksheet
C. Traffic Noise Model Calculations
D. Operational Noise Model Input Worksheets
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Acronyms and Abbreviations
Acronym/Abbreviation Definition
ACC air-cooled condenser
ADT average daily traffic
AUF acoustical usage factor
Caltrans California Department of Transportation
City City of San Marcos
CNEL Community Noise Equivalent Level
dB decibel
dBA A-weighted decibel
FHWA Federal Highway Administration
FTA Federal Transit Administration
HVAC heating, ventilating, and air-conditioning
ips inches per second
Ldn day–night average noise level
Leq equivalent noise level
Lmax maximum sound level
Lmin minimum sound level
PPV peak particle velocity
Project Marcos Specific Plan
RCNM Roadway Construction Noise Model
SF square feet
SLM sound level meter
SPL sound pressure level
veh/hr vehicles per hour
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1 Introduction and Background
This technical noise report evaluates the potential noise and vibration impacts during construction and operation of the proposed Marcos Specific Plan project (proposed Project, formerly known as Artist’s Village). This assessment utilizes the significance thresholds in Appendix G of the California Environmental Quality Act Guidelines (14 CCR 15000 et seq.).
Project Description
The proposed Marcos Specific Plan Project (project) includes a request for approval of a Specific Plan, General Plan Amendment, Rezone, Site Development Plan, Multi-Family Site Development Plan, Conditional Use Permit, Tentative Subdivision Map, and a Tentative Parcel Map for a residential mixed-use development project within the 12.06-acre Specific Plan Area. The General Plan Amendment and Rezone would change the General Plan designation and Zoning from Commercial (C) to Specific Plan Area (SPA). The Marcos Specific Plan has been prepared with the intent to provide a comprehensive plan to ensure the efficient development of a multi-land use development. The Specific Plan serves as both a policy document and a regulatory document for the systematic implementation of the policies and goals of the General Plan.
The project site is located at the northwest corner of Grand Avenue and Linda Vista Drive in the City of San Marcos (APNs 219-152-42, -44, -45, -51, -61, -70, -74, -75, -76, -77, -78, -79). Please refer to Figure 1, Project Location and Figure 2, Project Site. The existing project site has been previously disturbed and developed. Previous structures on- site have been demolished, and the site currently is vacant with remaining paved areas, billboards, and the bridge crossing over Las Posas Creek. Channel improvement work associated with the segment of Las Posas Creek that runs through the project site, and the associated bridge over the channel, was previously permitted by the City of San Marcos, and the channel is currently subject to restoration maintenance activities following channel improvements within the permitted conservation easement area. The project site is located in an urban area of the City surrounded by commercial and industrial uses to the north, east, and west, as well as undeveloped land to the south. The project site is located just south of State Route 78.
The project consists of construction of 102 multi-family residential units on 5.03 acres of the project site, and construction of 7,658 square feet (sf) of office space, 49,266 sf of specialty retail space and 7 live-work units on 6.05 acres of the project site (Figure 3, Site Plan). Residential units would be contained within 15 townhome buildings, and units would be a mix of six different unit types, ranging in size from two- to three-bedrooms. Additionally, the residential area would include a pool building, pool and spa area, barbeque area, picnic area, and play area for residents. The residential buildings would be located on the northwestern portion of the site, and commercial uses would be placed along the southern and eastern project boundaries. Access to the residential area would be provided via Grand Avenue at a northern driveway, and access to the commercial area would be via Grand Avenue at a southern driveway and two driveways along Linda Vista Drive. The project would provide 204 garage parking spaces for residences, 34 residential guest parking spaces, and 278 commercial parking spaces.
Noise Characteristics
Sound is mechanical energy transmitted by pressure waves in a compressible medium, such as air. Noise is defined as sound that is loud, unpleasant, unexpected, or undesired. The sound pressure level (SPL) has become the most common descriptor used to characterize the loudness of an ambient sound level. The unit of measurement of sound pressure is a decibel (dB). Under controlled conditions in an acoustics laboratory, the trained, healthy human ear is able to discern changes in sound levels of 1 dB when exposed to steady, single-frequency signals in the mid-
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frequency range. Outside such controlled conditions, the trained ear can detect changes of 2 dB in normal environmental noise. It is widely accepted that the average healthy ear, however, can barely perceive noise level changes of 3 dB. A change of 5 dB is readily perceptible, and an upward change of 10 dB is perceived as twice as loud (Caltrans 2013). A doubling of sound energy results in a 3 dB increase in sound, which means that a doubling of sound energy (e.g., doubling the number of ground vehicle daily trips along a given road segment) would result in a barely perceptible change in sound level.
Sound may be described in terms of level or amplitude (measured in dB), frequency or pitch (measured in hertz [Hz] or cycles per second), and duration (measured in seconds or minutes). Because the human ear is not equally sensitive to sound at all frequencies, a special frequency-dependent rating scale is used to relate noise to human sensitivity. The A-weighted decibel (dBA) scale performs this compensation by discriminating against low and very high frequencies in a manner approximating the sensitivity of the human ear.
Several descriptors of noise (noise metrics) exist to help predict average community reactions to the adverse effects of environmental noise, including traffic-generated noise. These descriptors include the equivalent noise level over a given period (Leq), the day–night average noise level (Ldn), and the community noise equivalent level (CNEL). Each of these descriptors uses units of dBA.
Leq is a decibel quantity that represents the constant or energy-averaged value equivalent to the amount of variable sound energy received by a receptor during a time interval. For example, a 1-hour Leq measurement of 60 dBA would represent the average amount of energy contained in all the noise that occurred in that hour. Leq is an effective noise descriptor because of its ability to assess the total time-varying effects of noise on sensitive receptors, which can then be compared to an established Leq standard or threshold of the same duration. Another descriptor is maximum sound level (Lmax), which is the greatest sound level measured during a designated time interval or event. The minimum sound level (Lmin) is often called the floor of a measurement period.
Unlike the Leq, Lmax, and Lmin metrics, Ldn and CNEL descriptors always represent 24-hour periods and differ from a 24-hour Leq value because they apply a time-weighted factor designed to emphasize noise events that occur during the non-daytime hours (when speech and sleep disturbance is of more concern). Time-weighted refers to the fact that Ldn and CNEL penalize noise that occurs during certain sensitive periods. In the case of CNEL, noise occurring during the daytime (7:00 a.m. to 7:00 p.m.) receives no penalty. Noise during the evening (7:00 p.m. to 10:00 p.m.) is penalized by adding 5 dB, and nighttime (10:00 p.m. to 7:00 a.m.) noise is penalized by adding 10 dB. Ldn differs from CNEL in that the daytime period is longer (defined instead as 7:00 a.m. to 10:00 p.m.), thus eliminating the dB adjustment for the evening period. Ldn and CNEL are the predominant criteria used to measure roadway noise affecting residential receptors. These two metrics generally differ from one another by no more than 0.5–1 dB, and are often considered or actually defined as being essentially equivalent by many jurisdictions.
Vibration Fundamentals
Vibration is oscillatory movement of mass (typically a solid) over time. It is described in terms of frequency and amplitude and, unlike sound, can be expressed as displacement, velocity, or acceleration. For environmental studies, vibration is often studied as a velocity that, akin to the discussion of sound pressure levels, can also be expressed in dB as a way to cast a large range of quantities into a more convenient scale. Vibration impacts to buildings are generally discussed in terms of inches per second (ips) peak particle velocity (PPV), which will be used herein to discuss vibration levels for ease of reading and comparison with relevant standards. Vibration can also be annoying and thereby impact occupants of structures, and vibration of sufficient amplitude can disrupt sensitive equipment and processes (Caltrans 2020), such as those involving the use of electron microscopes and lithography equipment. Common sources of vibration within communities include construction activities and railroads.
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Groundborne vibration generated by construction projects is usually highest during pile driving, rock blasting, soil compacting, jack hammering, and demolition-related activities where sudden releases of subterranean energy or powerful impacts of tools on hard materials occur. Depending on their distances to a sensitive receptor, operation of large bulldozers, graders, loaded dump trucks, or other heavy construction equipment and vehicles on a construction site also have the potential to cause high vibration amplitudes. The maximum vibration level standard used by the California Department of Transportation (Caltrans) for the prevention of structural damage to typical residential buildings is 0.3 ips PPV (Caltrans 2020).
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Figure 1 Project Location
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Figure 2 Project Site
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Figure 3 Site Plan
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2 Regulatory Setting
State
California Code of Regulations
California Government Code Section 65302(f) mandates that the legislative body of each county and city adopt a noise element as part of its comprehensive general plan. The local noise element must recognize the land use compatibility guidelines established by the State Department of Health Services. The guidelines rank noise land use compatibility in terms of “normally acceptable”, “conditionally acceptable”, “normally unacceptable”, and “clearly unacceptable” noise levels for various land use types. Single-family homes are “normally acceptable” in exterior noise environments up to 60 dBA CNEL and “conditionally acceptable” up to 70 dBA CNEL. Multiple-family residential uses are “normally acceptable” up to dBA 65 CNEL and “conditionally acceptable” up to dBA 70 CNEL.
Schools, libraries, and churches are “normally acceptable” up to 70 dBA CNEL, as are office buildings and business, commercial, and professional uses.
California Department of Transportation
In its Transportation and Construction Vibration Guidance Manual, Caltrans recommends a vibration velocity threshold of 0.2 ips PPV (Caltrans 2020) for assessing annoying vibration impacts to occupants of residential structures. Although this Caltrans guidance is not a regulation, it can serve as a quantified standard in the absence of such limits at the local jurisdictional level. Similarly, thresholds to assess building damage risk due to construction vibration vary with the type of structure and its fragility, but tend to range between 0.2 ips and 0.3 ips PPV for typical residential structures (Caltrans 2020).
Local
City of San Marcos Noise Level Compatibility Standards
The Noise Element of the City of San Marcos General Plan (City of San Marcos 2012) establishes target maximum noise levels in the City. Exhibit A (Table 7-3 of the Noise Element) depicts “acceptable,” “conditionally acceptable,” and “unacceptable” transportation-related exterior noise levels for the indicated land use designations.
With respect to commercial/industrial developments like the proposed Project, the Noise Element states: “the City should consider noise generation and potential impacts to surrounding development. New development can be made compatible with the noise environment by using noise and land use compatibility standards… as a guide for planning and development decisions. During the project design review process, the City can work with the project applicant to identify of potential impacts and reasonable mitigation measures. For example, the City can require an acoustical analysis for projects that will potentially generate noise that would affect sensitive receptors. These mitigation measures can include, but not be limited to, acoustically treated and/or quiet designs for furnaces, fans, motors, compressors, valves, pumps and other mechanical equipment. The City may also require limited delivery hours and/or hours of operation in order to reduce impacts to adjacent sensitive uses. In addition, all City departments must comply with State and federal OSHA standards. Any new equipment or vehicles purchased by the City will comply with local, State and federal noise standards.”
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Exhibit A. Reproduction of Table 7-3 from the City of San Marcos General Plan Noise Element Source: City of San Marcos (2012)
Relevant City General Plan Noise Element policies include as follows:
Policy N-1.1: Address the potential for excessive noise levels when making land use planning decisions in accordance with Table 7-3 Land Use Compatibility Noise Standards. Policy N-1.2: Ensure that acceptable noise levels are maintained near noise-sensitive uses.
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Policy N-1.4: Require new development projects to provide barriers to reduce noise levels, or provide sufficient spatial buffers to separate excessive noise generating land uses and noise-sensitive land uses. Policy N-1.5: Require an acoustical study for proposed developments in areas where the existing and projected noise level exceeds or would exceed the Normally Acceptable levels identified in Table 7-3. Policy N-3.4: Avoid excessive noise of commercial and industrial land uses through site and building design features.
The City’s General Plan also specifies exterior noise level standards. Exhibit B (Table 7-4 of the Noise Element) depicts the exterior noise standards by the Land Use Category shown in Exhibit A.
Exhibit B Reproduction of Table 7-4 from the City of San Marcos General Plan Noise Element
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City of San Marcos Noise Ordinance
The City of San Marcos Municipal Code Chapter 10.24: Noise (San Marcos 2017) addresses construction noise.
Erection and demolition of buildings is exempt between 7:00 a.m. and 6:00 p.m. Monday through Friday and on Saturdays from 8:00 a.m. to 5:00 p.m. The Municipal Codes does not set noise limits on construction activities.
Commonly, the City has utilized the County of San Diego’s Noise Ordinance construction noise limit of 75 dBA (8- hour average) as received by occupied properties. Treating construction noise as a type of non-transportation noise, this is supported by the following from Chapter 7 of the San Marcos General Plan (i.e., Noise Element): “San Marcos relies on the San Diego County Noise standards to regulate land use noise compatibility, transportation noise, and non-transportation noise” (City of San Marcos 2012).
Chapter 20.300 (Site Planning and General Development Standards) of the City’s Municipal Code includes noise regulations in the form of noise standards by zone (Section 20.300.070, Performance Standards). It should be noted that Municipal Code noise standards typically pertain to stationary (i.e., non-transportation-related) noise sources. The relevant portions of these noise standards are provided below:
1. Noise shall be measured with a sound-level meter that meets the standards of the American National Standards Institute (ANSI) (Section S1.4-1979, Type 1 or Type 2). Noise levels shall be measured in decibels at the property line of the receptor property, and at least five (5) feet above the ground and ten (10) feet from the nearest structure or wall. The unit of measure shall be designated as an A-weighted decibel (dBA) Leq standard. A calibration check shall be made of the instrument at the time any noise measurement is made (Ord. No. 2017-1446, 7-25-2017)
2. No person shall create or allow the creation of exterior noise that causes the noise level to exceed the noise standards established by Table 20.300-4 (shown in this report as Table 1). Increases in exterior noise levels listed in Table 20.300-4 are permitted but depend on cumulative duration of the increase within the measured hour. For instance, a 5 dB increase is allowed for up to fifteen (15) minutes within the hour, but a 10 dB increase above the limit is allowed for up to 5 cumulative minutes within that hour.
3. Use of compressors or other equipment, including vents, ducts, and conduits, but excluding window or wall- mounted air conditioners, that are located outside of the exterior walls of any building, shall be enclosed within a permanent, non-combustible, view-obscuring enclosure to ensure that the equipment does not emit noise in excess of the ANSI standards.
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Table 1. City of San Marcos Exterior Noise Standards
Zone Applicable Limit (decibels) Time Period
Single-Family Residential (A, R-1, R-2) 1, 2 60
50 7:00 a.m. to 10:00 p.m.
10:00 p.m. to 7:00 a.m.
Multifamily Residential (R-3) 1, 2 65
55 7:00 a.m. to 10:00 p.m.
10:00 p.m. to 7:00 a.m.
Commercial (C, O-P, SR) 3 65
55 7:00 a.m. to 10:00 p.m.
10:00 p.m. to 7:00 a.m.
Industrial 65
60 7:00 a.m. to 10:00 p.m.
10:00 p.m. to 7:00 a.m.
Source: San Marcos 2017 (Table 20.300-4)
Notes:
1. For single-family detached dwelling units, the "exterior noise level" is defined as the noise level measured at an outdoor living area which adjoins and is on the same lot as the dwelling, and which contains at least the following minimum net lot area: (i) for lots less than 4,000 square feet in area, the exterior area shall include 400 square feet, (ii) for lots between 4,000 square feet to 10 acres in area, the exterior area shall include 10 percent of the lot area; (iii) for lots over 10 acres in area, the exterior area shall include 1 acre.
2. For all other residential land uses, "exterior noise level" is defined as noise measured at exterior areas which are provided for private or group usable open space purposes. "Private Usable Open Space" is defined as usable open space intended for use of occupants of one dwelling unit, normally including yards, decks, and balconies. When the noise limit for Private Usable Open Space cannot be met, then a Group Usable Open Space that meets the exterior noise level standard shall be provided. "Group Usable Open Space" is defined as usable open space intended for common use by occupants of a development, either privately owned and maintained or dedicated to a public agency, normally including swimming pools, recreation courts, patios, open landscaped areas, and greenbelts with pedestrian walkways and equestrian and bicycle trails, but not including off-street parking and loading areas or driveways.
3. For non-residential noise sensitive land uses, exterior noise level is defined as noise measured at the exterior area provided for public use.
Marcos Specific Plan
The Marcos Specific Plan Section 2.6.7, Noise, establishes a limit on exterior noise levels at the Specific Plan boundary. The Specific Plan states that “noise attenuation techniques shall be employed, as needed, to ensure noise levels remain at or below 65 dBA Leq at the specific plan boundary.” Further, the Specific Plan states that “each design feature and construction mitigation measure will conform the project to the City’s General Plan Noise Element requirements.”
The Marcos Specific Plan also addresses noise from events expected to be held at outdoor use spaces. Section
3.6.1.4, Events and Entertainment, (A.3) states that “events and entertainment may occur from 10 a.m. to 10 p.m.
Noise Shall not exceed 65 dBA Leq at the property line per SMMC 20.300.070E.”
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3 Existing Conditions
Sound pressure level (SPL) measurements were conducted near the Project site on December 14, 2022, to quantify and characterize samples of the existing (a.k.a., baseline or pre-project) outdoor sound environment. Table 2 provides the location (and adjoining land use) and time at which these baseline noise level measurements were taken. The SPL measurements were performed by an attending Dudek field investigator using a Rion NL-52 sound level meter equipped with a 0.5-inch, pre-polarized condenser microphone with pre-amplifier. The sound level meter meets the current American National Standards Institute standard for a Type 1 (Precision Grade) sound level meter (SLM). The accuracy of the SLM was verified in the field using a reference sound signal (i.e., field calibrator) before and after the measurements, and the measurements were conducted with the microphone positioned approximately 5 feet above the ground.
Three short-term noise level measurement locations (ST1, ST2, and ST3) are depicted on Exhibit C. Table 2 presents Leq, Lmax, and Lmin values for these surveyed positions, which were affected by the investigator-noted acoustical contributors as follows:
ST1 – Traffic;
ST2 – Traffic and distant industrial,
ST3 – Traffic, birdsong, distant aircraft, and distant traffic.
As shown in Table 2, the measured sound levels ranged from approximately 64.0 dBA Leq at ST2 to 76.7 dBA Leq at ST1. Noise measurement data and photographs of the survey locations appear in Appendix A, Baseline Noise Measurement Field Data. These samples of daytime Leq measured at the three representative receptor positions in Table 2 can be interpreted as approximations of CNEL, since evening SPL would likely be 5 dBA less, and nighttime SPL would be 10 dBA less than the daytime values (Federal Transit Administration [FTA] 2018).
Table 2. December 14, 2022 Measured Outdoor Ambient Sound Environment Samples Survey
Position Location/Address
Start and End Time
(hh:mm)
Leq
(dBA)
Lmax
(dBA)
Lmin
(dBA)
ST1 Northeast of the Project site,
between Grand Ave. and CA-78 11:20 a.m. to 11:25 a.m. 76.7 84.8 70.5 ST2 Southern edge of the Project site,
north of Linda Vista Dr. 11:35 a.m. to 11:50 a.m. 64.0 72.5 57.2 ST3
Adjacent to the building at 237 Via
Vera Cruz, west of the Project site
and east of Via Vera Cruz
11:40 a.m. to 11:50 a.m. 67.6 82.7 52.2
Source: Appendix A.
Notes: Leq = equivalent continuous sound level (time-averaged sound level); Lmax = maximum sound level during the measurement interval; dBA = A-weighted decibels; ST = short-term noise measurement locations.
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Exhibit C. Baseline Outdoor Ambient Sound Level Measurement Positions
Sources: Google Earth 2022, Dudek 2022
ST3
ST1
ST2
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4 Thresholds of Significance
The following significance criteria are based on Appendix G of the California Environmental Quality Act Guidelines (14 CCR 15000 et seq.) and will be used to determine the significance of potential noise impacts. Impacts to noise would be significant if the proposed project would result in the following:
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
b. Generation of excessive groundborne vibration or groundborne noise levels c. Expose people residing or working in the project area to excessive noise levels (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 2 miles of a public airport or public use airport) In light of these above significance criteria, this analysis uses the following standards to evaluate potential noise and vibration impacts.
Construction noise – the City has adopted the County’s construction noise threshold of not exceeding 75 dBA for an eight-hour period, between 7:00 a.m. and 7:00 p.m., when measured at any occupied property where the noise is being received.
Off-site Project-attributed transportation noise – For purposes for this analysis, a direct roadway noise impact would be considered significant if increases in roadway traffic noise levels attributed to the proposed project were greater than 3 dBA CNEL at an existing noise-sensitive land use. Off-site Project-attributed stationary noise – For purposes for this analysis, a noise impact would be considered significant if noise from onsite Project sound sources, including typical operation of heating, ventilation, and air conditioning (HVAC), other electro-mechanical systems, as well as outdoor events, exceeded 65 dBA hourly Leq at the property line from 7:00 a.m. to 10:00 p.m., and 55 dBA hourly Leq from 10:00 p.m. to 7:00 a.m.
Construction vibration – Guidance from Caltrans indicates that a vibration velocity level of 0.2 ips PPV received at a structure would be considered annoying by occupants within (Caltrans 2020). As for the receiving structure itself, aforementioned Caltrans guidance from Section 2 recommends that a vibration level of 0.3 ips PPV would represent the threshold for building damage risk.
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5 Impact Discussion
a) Would the project result in 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?
Short-Term Construction
Construction noise and vibration are temporary phenomena, varying from hour to hour and day to day, depending on the equipment in use, the operations performed, and the distance between the source and receptor. Equipment that would be in use during construction would include, in part, graders, scrapers, backhoes, rubber-tired dozers, loaders, cranes, forklifts, cement mixers, pavers, rollers, and air compressors. The typical maximum noise levels for various pieces of construction equipment at a distance of 50 feet are presented in Table 3. Usually, construction equipment operates in alternating cycles of full power and low power, which the Federal Highway Administration (FHWA) Roadway Construction Noise Model (RCNM) User’s Guide (FHWA 2006) characterizes as “acoustical usage factor” (AUF) and thereby produces energy-average noise levels over time (Leq) that are less than the listed maximum noise level (Lmax). The average sound level of construction activity also depends on the amount of time that the equipment actually operates onsite.
Table 3. Typical Construction Equipment Maximum Noise Levels FHWA RCNM Equipment Type
Acoustical Usage
Factor (%)
Typical Equipment Lmax
(dBA at 50 Feet)
Typical Equipment Leq
(dBA at 50 Feet)
all other equipment > 5 HP 50 85 82
backhoe 40 78 74
compressor (air) 40 78 74
concrete mixer truck 40 79 75
crane 16 81 73
dozer 40 82 78
generator 50 72 69
grader 40 85 81
man lift 20 75 68
paver 50 77 74
roller 20 80 73
scraper 40 84 80
welder / torch 40 73 69
Source: FHWA 2006.
Note: Lmax = maximum sound level; where Leq = energy-equivalent sound level and can be calculated here with Leq = Lmax + 10*LOG(AUF); dBA = A-weighted decibels.
Using the provided construction information, prediction results are summarized in Table 4 at the nearest noise- sensitive receptor for two calculation scenarios as follows:
Usage of the shortest activity-to-receptor distance for the loudest equipment type and quantity associated with the studied construction phase, with less noisy equipment types at successive distance increments of 50 feet; and
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An “acoustic centroid” approach, akin to the Federal Transit Administration (FTA) general assessment technique for estimating construction noise, whereby all listed equipment for a construction phases is represented by a common location at the geographic center of the studied construction zone or area.
The first of these methods is considered a conservative approach to assess what might be characterized as a peak exposure level, applicable to not more than approximately 10%–15% of the total construction period and when the studied construction activity is taking place with loudest equipment along the property boundary closest to these nearest off-site receivers. The second approach utilizes the acoustic centroid technique to represent a time- averaged location for the phase equipment and activity, thereby yielding average noise levels to represent overall noise exposure as experienced for adjacent receivers over the duration of each construction phase.
A Microsoft Excel–based noise prediction model emulating and using reference data from the FHWA RCNM (FHWA 2008) was used to estimate construction noise levels. (Although the RCNM was funded and promulgated by the Federal Highway Administration, it is often used for non-roadway projects, because the same types of construction equipment used for roadway projects are often used for other types of construction.) Input variables for the predictive modeling consist of the equipment type and number of each, the afore-mentioned AUF, the expected duration (in hours) of onsite activity, and the distance from the receiver. Conservatively, no topographical or structural shielding was assumed in the modeling.
Appendix B displays the construction noise model worksheets for each of these analysis approaches. Although the quantities and types of equipment per construction phase are the same in each of the two approaches, due primarily to the differences in source-to-receptor distance variables, Table 4 shows that prediction results of both scenarios.
Table 4. Predicted Construction Noise Levels per Activity Phase Construction Phase (and Equipment Types
Involved)
8-Hour Leq Closest Distance
to Nearest Noise Sensitive
Receptor (dBA)
8-Hour Leq Acoustic Center to
Nearest Noise Sensitive
Receptor (dBA)
Feet dBA Feet dBA
Demolition (concrete saw, excavator, dozer) 1,120 51.0 1,310 57.9 Site preparation (dozer, tractor, front end
loader, backhoe) 1,060 53.5 1,300 58.2
Grading (excavator, grader, dozer, tractor, front
end loader, scraper) 1,060 54.5 1,300 58.9
Building construction (crane, man-lift, generator,
tractor, front end loader, backhoe, welder/torch) 1,100 51.9 1,290 53.9 Paving (paver, paving equipment, roller) 1,090 55.2 1,350 57.5 Architectural coating (air compressor) 1,100 45.9 1,290 44.5 Notes: Leq = equivalent noise level; dBA = A-weighted decibels.
As presented in Table 4, the estimated construction noise exposure levels for each of the five expected sequential phases are not predicted to exceed 75 dBA Leq over an 8-hour period at the nearest noise sensitive receptors to the north of the Project site. The predicted construction noise levels ranging from 45 to 58 dBA Leq over an 8-hour period at the nearest noise sensitive receptor are also comparable to (or less than) the measured baseline outdoor sound level of 64 dBA at survey position “ST2” shown in Table 2. For these reasons, temporary construction-related noise impacts would be considered less than significant.
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Long-Term Operational
Off-Site Roadway Traffic Noise
The proposed Project would result in the creation of additional vehicle trips on local roadways (i.e., Linda Vista Drive, Grand Avenue, and Via Vera Cruz), which could result in increased traffic noise levels at adjacent noise-sensitive land uses. The Project is expected to generate a net total of 2,241 daily trips to the roadway system. As shown in Table 3.1 of the Project’s Transportation Impact Study, during the PM peak-hour, approximately 189 vehicles are estimated to enter or exit the Project site. Utilizing this information, an emulator based on the FHWA’s Highway Traffic Noise Prediction Model RD-77-108 was used to estimate potential noise impacts at adjacent noise-sensitive uses. Information used in the model included posted traffic speeds, truck mix percentage, and average daily traffic (ADT) volumes (expressed as vehicles per hour) for the existing, near-term year 2024 with and without Project, and horizon year 2050 with and without Project conditions.
ADT volumes for I-78 were obtained separately via the San Diego Association of Governments (SANDAG) Transportation Forecast Information Center (TFIC) for the existing (2016), near-term (2025), and horizon (2050) years. Existing (2022) and Near-Term (2024) ADT volumes for I-78 were derived by determining the yearly percentage increase or decrease in traffic using the information available from the TFIC.
Consistent with Caltrans guidance (Caltrans, 2013), this analysis assumes 80% of the ADT occurs during daytime hours (7:00 a.m. to 7:00 p.m.), 5% during the evening (7:00 p.m. to 10:00 p.m.), and 15% during the nighttime (10:00 p.m. to 7:00 a.m.). Appendix C, Traffic Noise Model Calculations, contains the input data and results of the traffic noise modeling effort. According to acoustical principles, the increase in traffic noise level relates directly to the increase in volumes by the following expression: 10*LOG(Vf/Ve), where Vf is the future traffic volume, Ve is the existing traffic volume, and vehicle speeds and proportion of vehicle types are essentially unchanged. The Project would therefore have to roughly double the traffic volumes on nearby studied roadway segments in order to increase traffic by 3 dBA, which would be considered a barely perceptible increase (Caltrans 2013).
Traffic noise levels were modeled at the same geographic positions for ST2 and ST3 as shown in Exhibit B. The traffic noise level for ST1 was predicted at the northwestern boundary of the Project site in order to be representative of the future residences located behind a proposed six-foot noise wall. The traffic noise model results are summarized in Table 5, and represented by CNEL values.
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Table 5. Off-site Roadway Traffic Noise Modeling Results Modeled Receiver Tag (and
Location Description)
Existing
(2022)
Noise Level
(CNEL)
Near-Term
(2024)
Without
Project
(CNEL)
Near-Term
(2024)
With
Project
(CNEL)
Project-
Related
Near-Term
(2024)
Noise
Level
Increase
(dB)
Horizon
(2050)
Without
Project
(CNEL)
Horizon
(2050)
With
Project
(CNEL)
Project-
Related
Horizon
(2050)
Noise
Level
Increase
(dB)
ST1 (Northeastern boundary of
the Project site, adjacent to
Grand Ave. and CA-78)
76.6 76.5 73.8 -2.7 75.9 73.5 -2.4
ST2 (Southern edge of the
Project site, north of Linda Vista
Dr.)
67.3 67.3 68.3 1.1 67.5 68.5 1.0
ST3 ( Adjacent to the building at
237 Via Vera Cruz, west of the
Project site and east of Via Vera
Cruz)
67.2 67.2 67.4 0.2 69.0 69.1 0.1
Notes: dBA = A-weighted decibel; CNEL = Community Noise Equivalent Level; dB = decibel.
Table 5 shows that at all three listed representative receivers, the addition of proposed Project traffic to the local roadway network would result in a CNEL increase of less than or equal 1 dB, which is below the discernible level of change for the average healthy human ear. Thus, a less-than-significant impact is expected for proposed project- related off-site traffic noise increases affecting existing residences in the vicinity.
On-Site Roadway Traffic Noise
As of January 2019, the study of future Project residential exposures to offsite transportation noise sources is not considered for noise impact assessment at the California state level. Hence, for informational purposes and as shown in Table 5, predicted future (2024 and 2050) “with project” noise levels exceed the City’s “conditionally acceptable” multi-family/mixed-use land use compatibility standard threshold of 75 dBA CNEL at the receiver representing the multi-family residences located adjacent to Grand Avenue. The proposed six-foot noise wall on the northeastern side of the property, situated between the Project buildings and the parallel major roadway represented by Grand Avenue and CA-78 traffic, is predicted to provide an insertion loss of approximately three to four dBA for first-floor exterior areas.
Second floor balconies (as shown in Exhibit D) facing Grand Avenue and CA-78 are also predicted to exceed 75 dBA CNEL, but would not be benefited by the additional three to four dBA of insertion loss from the six-foot noise wall.
If these balconies are not merely an architectural or decorative feature and are intended to be used as private outdoor spaces with the potential to be occupied by residents or their guests, then those balconies would need to be acoustically upgraded in order to reduce outdoor noise exposure for seated occupants.
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Exhibit D. Project Multi-Family Residential Building with Balconies Facing Grand Avenue and CA-78 Source: Lab Holding, LLC California Pacific Homes (2022) Note: Balconies are encircled in red
An approach that Dudek has recommended on previous residential projects is to provide this identified noise reduction need by way of the addition of a solid and sufficiently massive material layer to the planned square-tubed metal railings on the balcony usable area perimeter. As depicted in Exhibit E, showing detail from a previously studied project (and thus used merely for illustration purposes), proposed installation of a 6-millimeter (0.236 inch) sheet of plexiglass (acrylic) on the interior-facing side of the balcony railing structure would be expected to yield an effective sound transmission class (STC) rating of at least 15. Although the material itself has an STC rating of 29 (Arkema Group 2019), the approximate 1”-wide air gap between the bottom edge of the plexiglass panel and the balcony floor results in lower expected STC performance. In other words, the area of the gap as a fraction of the barrier material surface area causes the reduction in sound transmission loss performance. Other material options and designs are possible, subject to non-acoustical considerations such as desired barrier opacity, balcony deck drainage, etc., provided that the designed installation has barrier material having adequate mass and solidity, an approximate deck to top-edge height of 42 inches (3.5 feet), and with minimized air-gaps such as the sample appearing in Exhibit E.
Exhibit F illustrates examples of similar sound-blocking balcony barriers to help reduce incoming traffic noise and increase occupant privacy at pre-existing Vista Flores Apartments and Barham Villas Apartments that overlook and are within comparable horizontal distances to the CA-78 highway as anticipated Project facades appearing in Exhibit D.
On these bases, implementation of PDF-NOI-1 and PDF-NOI-2 below would help reduce traffic noise exposure levels.
However, predicted traffic noise exposure levels may still exceed the City’s land use compatibility standard of 65 dBA CNEL at the Private Usable Open Spaces for these Category B receptors per Table 7-4 (as shown in Exhibit B).
As permitted by note 5 in Table 7-4, the Project’s group Usable Open Spaces (pool, playground, etc.) that are shielded by multiple Project building rows would be predicted to have traffic noise exposure levels less than 65 dBA CNEL and would therefore be compatible with the City’s land use compatibility standard. This is supported by language in note 5 from Table 7-4 as follows: “When the noise limit for Private Usable Open Space cannot be met, then a Group Usable Open Space that meets the exterior noise level standard shall be provided.”
PDF-NOI-1 Where Project exterior onsite noise levels due to offsite surface transportation noise sources are predicted to exceed 65 dBA CNEL at useable open space areas, the Project shall install noise-
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reducing features external to or upon the useable open space areas (or within, as practical and appropriate) in the form of sound walls, fencing, landscape berms, or similarly performing barriers to occlude incoming roadway traffic noise.
PDF-NOI-2 Residential unit patios or balconies with roadway-facing building facades predicted to be exposed to external noise levels in excess of 65 A-weighted decibels community noise equivalent level shall feature railings or other partial-height barriers comprising sufficiently solid and dense materials (e.g., acrylic, glass, wood that exhibits a sound transmission class rating of at least 20) and of a 42-inch minimum height (from floor or deck of the balcony surface) that occludes direct sound path from the noise-producing roadway of concern and a seated patio or balcony occupant.
Exhibit E. Elevation view of a typical balcony railing, with a recommended 6-millimeter plexiglass element added for noise reduction
Sources: Humphreys 2019, Dudek 2020
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Exhibit F. Samples of Balcony Barriers at Multi-Family Residential Land Uses along CA-78 (left: northern façade of Barham Villas Apartments building; right: southern façade of Vista Flores Apartments building) Source: Google Earth Pro 2023
Stationary Project Operations Noise
The completion of various buildings on the Project site will add a variety of noise-producing mechanical equipment that include those presented and discussed in the following paragraphs. In addition to noise-producing mechanical equipment on the roofs of the Project buildings, the site contains several proposed outdoor spaces on the east side of the site where events are expected to take place. Most of these noise-producing equipment or sound sources would be considered stationary or limited in mobility to a defined area.
The aggregate noise emission from these outdoor-exposed sound sources has been predicted with the Datakustik CadnaA sound propagation program. CadnaA is a commercially available software program for the calculation, presentation, assessment, and prediction of environmental noise based on algorithms and reference data per International Organization of Standardization (ISO) Standard 9613-2, “Attenuation of Sound During Propagation Outdoors, Part 2: General Method of Calculation” (ISO 1996). The CadnaA computer software allows one to position sources of sound emission in a simulated three-dimensional (3-D) space atop rendered “blocks” of project building masses having heights and footprints consistent with project architectural plans and elevations. In addition to the above-mentioned sound source inputs and building-block structures that define the three-dimensional sound propagation model space, the following assumptions and parameters are included in this CadnaA-supported stationary noise source assessment:
Ground effect acoustical absorption coefficient equal to 0.5, which intends to represent an average or blending of ground covers that are characterized largely by hard reflective pavements and existing building surfaces across the Project site and the surroundings; Reflection order of 1, which allows for a single reflection of sound paths on encountered structural surfaces such as the modeled building masses;
Off-site residential structures and the commercial buildings have not been rendered in the model; Calm meteorological conditions (i.e., no wind) with 68 degrees Fahrenheit and 50% relative humidity; and All of the modeled noise sources are operating concurrently and continuously for a minimum period of 1 hour.
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HVAC Noise
The proposed Project buildings would be served by air-conditioning equipment that includes outdoor-exposed packaged air-handling units or—at a minimum—air-cooled condensers (ACC) that provide the expected cooling demand (expressed as refrigeration “tonnage”) for the building.
Based on the available architectural plans and other design information for the proposed Project, there are a number of HVAC units proposed on the roof of each Project building. Rooftop HVAC reference sound levels were calculated from a combination of inputs that include the gross square footage (SF) values for the Project’s residential and commercial facilities, Project applicant response to data requests, and manufacturer sound power level data.
Table 6 presents the predicted aggregate noise level exposures from the operating rooftop HVAC systems at each of four (4) nearby receptors (i.e., short-term measurement locations and the closest noise-sensitive receptor).
Predicted levels shown in Table 6 range between 20 to 36 dBA hourly Leq, which is below the City’s noise standard of 60 dBA Leq for single-family residential properties and below the Marcos Specific Plan limit of 65 dBA Leq at the site boundary. Figure 4 displays the location of the studied receptors and noise contours for the HVAC-only condition. See Appendix D for quantitative details of the modeling inputs.
Table 6. HVAC Only Stationary Operations Noise Modeling Results Studied Noise-Sensitive Receptor
Predicted Project-Attributed Noise
Exposure Level at Nearby Receptors
Project HVAC (dBA hourly Leq)
ST1 35.7
ST2 33.6
ST3 23.2
Nearest Noise-Sensitive Receptor 20.3
Note: Leq = equivalent continuous sound level (time-averaged sound level); dBA = A-weighted decibels; HVAC = heating, ventilating, and air-conditioning. See Figure 4 for locations of studied noise-sensitive receptors for the HVAC only condition.
HVAC Plus Event Noise
Based on the information found in the Marcos Specific Plan Section 3.6.1.4, multiple event types and sizes will be allowed at the outdoor spaces developed by the Project. Anticipated event sizes are categorized by expected attendance and range from “small” (10-20 people) to “large” (100+ people).
For the same four (4) studied receptor positions listed in Table 6 (i.e., short-term measurement locations and the closest noise-sensitive receptor), and resulting from usage of the same CadnaA-based sound propagation prediction model, Table 7 presents the predicted aggregate noise level exposures from the operating rooftop HVAC systems and an in-progress event with 100 people at an outdoor use area on the east side of the commercial side of the Project. For purposes of this analysis, the added event-related noise would be considered equivalent to speech from one hundred speakers at an average “loud speaking” level (Hayne 2006) and geographically spread over the event area as shown in Figure 14 of the Marcos Specific Plan. Predicted levels shown in Table 7 range between 25 to 60 dBA hourly Leq, which is below the Marcos Specific Plan standard of 65 dBA Leq at the Specific Plan boundary.
Figure 5 displays the location of the studied receptors and noise contours for this studied HVAC-plus-event Project noise emission scenario.
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Table 7. HVAC Plus Event Stationary Operations Noise Modeling Results Studied Noise-Sensitive Receptor
Predicted Project-Attributed Noise
Exposure Level at Nearby Receptors
Project HVAC + Event (dBA hourly Leq)
ST1 36.1
ST2 60.1
ST3 39.4
Nearest Noise-Sensitive Receptor 25.3
Note: Leq = equivalent continuous sound level (time-averaged sound level); dBA = A-weighted decibels; HVAC = heating, ventilating, and air-conditioning. See Figure 3 for locations of studied noise-sensitive receptors for the HVAC plus event condition.
In summary, aggregate noise emission from continuously operating outdoor-exposed rooftop HVAC units is expected to be below the City’s exterior noise threshold of 60 dBA Leq for commercial land uses and below the Specific Plan threshold of 65 dBA Leq at the site boundary. Additionally, aggregate Project noise emission from the combination of this anticipated building HVAC noise and a “large” in-progress outdoor event attended by 100 people at the planned event area would be compliant with the Specific Plan threshold of 65 dBA Leq at the site boundary. Given that such a large attended outdoor event is predicted to be compliant, one can reasonably assume that an HVAC- plus-event noise emission associated with “small” outdoor events that may occur locally around distinct Project buildings would, on the basis of smaller event attendance having less acoustical contribution due to average speech levels, also be compliant with this Specific Plan standard.
Therefore, noise associated with stationary operations related to rooftop HVAC equipment would be considered a less than significant impact, and no mitigation is required.
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Figure 4 Aggregate Stationary Sources Operational Noise Level Prediction – HVAC Only
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Figure 5 Aggregate Stationary Sources Operational Noise Level Prediction – HVAC Plus Event
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b) Would the project result in generation of excessive groundborne vibration or groundborne noise levels? Construction activities may expose persons to excessive groundborne vibration or groundborne noise, causing a potentially significant impact. Caltrans has collected groundborne vibration information related to construction activities (Caltrans 2020). Information from Caltrans indicates that continuous vibrations with a PPV of approximately 0.2 ips is considered annoying. For context, heavier pieces of construction equipment, such as a bulldozer that may be expected on the project site, have peak particle velocities of approximately 0.089 ips PPV or less at a reference distance of 25 feet (FTA 2018).
Groundborne vibration attenuates rapidly, even over short distances. The attenuation of groundborne vibration as it propagates from source to receptor through intervening soils and rock strata can be estimated with expressions found in FTA and Caltrans guidance. By way of example, for a vibratory roller operating on site and as close as the southern project boundary (i.e., 30 feet from the nearest occupied building) when involved in the paving phase of Project construction, the estimated vibration velocity level would be 0.16 ips per the equation as follows (FTA 2018):
PPVrcvr = PPVref * (25/D)^1.5 = 0.16 = 0.21 * (25/30)^1.5 In the above equation, PPVrcvr is the predicted vibration velocity at the receiver position, PPVref is the reference value at 25 feet from the vibration source (the bulldozer), and D is the actual horizontal distance to the receiver. Therefore, at this predicted PPV, the impact of vibration-induced annoyance to occupants of nearby commercial buildings would be less than significant.
Construction vibration, at sufficiently high levels, can also present a building damage risk. However, anticipated construction vibration associated with the proposed project would yield levels of 0.16 ips PPV, which does not surpass the guidance limit of 0.3 ips PPV for preventing damage to older residential structures (Caltrans 2020).
Because the predicted vibration level at 30 feet is less than this guidance limit, the risk of vibration damage to nearby structures is considered less than significant.
Once operational, the proposed project would not be expected to feature major producers of groundborne vibration.
Anticipated mechanical systems like heating, ventilation, and air-conditioning units are designed and manufactured to feature rotating (fans, motors) and reciprocating (compressors) components that are well-balanced with isolated vibration within or external to the equipment casings. On this basis, potential vibration impacts due to proposed project operation would be less than significant.
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 of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? There are no private airstrips within the vicinity of the project site. The closest airport to the project site is the McClellan Palomar Airport, approximately 5 miles west of the site. According to the Comprehensive Land Use for McClellan-Palomar Airport (SDCRAA 2011) the Project site is not located within a noise exposure contour and would therefore not expose people residing or working in the project area to excessive noise levels.
Impacts from aviation overflight noise exposure would be less than significant.
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6 Mitigation Measures
The results indicate that potential impacts during construction and operation of the proposed Project would be less than significant. No mitigation is required with proper implementation of the Specific Plan.
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7 Summary of Findings
This noise report was conducted for the proposed Project. The results indicate that potential noise and vibration impacts during construction would be less than significant, and no noise or vibration mitigation is required.
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8 References Cited
Caltrans (California Department of Transportation). 2013. Technical Noise Supplement to the Traffic Noise Analysis Protocol. September. Accessed at https://dot.ca.gov/-/media/dot- media/programs/environmental-analysis/documents/env/tens-sep2013-a11y.pdf Caltrans. 2020. Transportation and Construction Vibration Guidance Manual. Division of Environmental Analysis, Environmental Engineering, Hazardous Waste, Air, Noise, Paleontology Office. Sacramento, California.
April. Accessed at https://dot.ca.gov/-/media/dot-media/programs/environmental- analysis/documents/env/tcvgm-apr2020-a11y.pdf
City of San Marcos. 2012. City of San Marcos General Plan, Noise Element. Accessed at https://www.san- marcos.net/home/showpublisheddocument/8475/636573113849130000 City of San Marcos. 2017. City of San Marcos Noise Ordinance (Chapter 10.24 and 20.300.070(F)). Accessed at https://library.municode.com/ca/san_marcos/codes/code_of_ordinances?nodeId=TIT10PUSAMOWE_C H10.24NO
City of San Marcos. 2022. Zoning Map. Accessed at http://maps2.san- marcos.net/mapgallery/map.html?webmap=0d07611e9fc64aefab39468b1f459409 CR Associates. 2022. San Marcos Artist’s Village Transportation Impact Study. November 2022.
Federal Highway Administration (FHWA). 2004. FHWA Traffic Noise Model Version 2.5.
Federal Transit Administration (FTA). 2018. Transit Noise and Vibration Impact Assessment Manual. FTA Report No. 0123. John A. Volpe National Transportation Systems Center. September. Accessed at https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/research-innovation/118131/transitnoise-and- vibration-impact-assessment-manual-fta-report-no-0123_0.pdf Federal Highway Administration (FHWA). 2008. Roadway Construction Noise Model (RCNM), Software Version 1.1.
U.S. Department of Transportation, Research and Innovative Technology Administration, John A. Volpe National Transportation Systems Center, Environmental Measurement and Modeling Division.
Washington, D.C. December 8, 2008.
Federal Highway Administration (FHWA). 2006. FHWA Roadway Construction Noise Model: User’s Guide. Final Report.
FHWA-HEP-06-015. DOT-VNTSC-FHWA-06-02. Cambridge, Massachusetts: DOT, Research and Innovative Technology Administration. August. Accessed January 25, 2022 at https://www.gsweventcenter.com/ Draft_SEIR_References/2006_01_Roadway_Construction_Noise_Model_User_Guide_FHWA.pdf.
Hayne, et al. 2006. “Prediction of Crowd Noise”. Proceedings of ACOUSTICS 2006. 20-22 November. Christchurch, NZ.
International Organization of Standardization (ISO). 1996. Standard 9613-2 (Acoustics – Attenuation of sound during propagation outdoors – Part 2: General method of calculation). Geneva.
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City of San Marcos. 2019. Sunrise Specific Plan EIR. Appendix I – Noise Report. https://files.ceqanet.opr.ca.gov/250156-
3/attachment/VgqRaqha0IrJuTEcMdvbe4aTCWZ7S5HPf287uGiiWrsyTmicmENLcNw- Te_dsNy5BozAXlXfowp5weo50
Lab Holding, LLC – California Pacific Homes. 2022. AOA San Marcos Site Plan.
Loren Cook. 1999. Engineering Cookbook. Second Edition.
CCi. 2022. Marcos Specific Plan.
San Diego Association of Governments (SANDAG). 2021. Transportation Forecast Information Center. https://tfic.sandag.org/
San Diego County Regional Airport Authority. 2011. McClellan-Palomar Compatibility Factor Maps. Accessed at https://www.san.org/DesktopModules/Bring2mind/DMX/API/Entries/Download?Command=Core_Downl oad&EntryId=2979&language=en-US&PortalId=0&TabId=225
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Appendix A
Baseline Noise Measurement Field Data (Dudek Forms)
Appendix B
Construction Noise Prediction Model Worksheet
Appendix C
Traffic Noise Model Calculations
Appendix D
Operational Noise Model Input Worksheets