kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
MEMORANDUM
To: Dana Privitt, Kimley-Horn and Associates, Inc.
From: Danielle Millar, Kimley-Horn and Associates, Inc.
Date: February 9, 2024
Subject: Clinton Keith Road and Mitchell Road Shopping Center Project – Murrieta, CA – Noise Analysis
Purpose
The purpose of this memorandum is to identify noise and vibration impacts associated with construction and operations of the proposed Clinton Keith Road and Mitchell Road Shopping Center Project (Project), located in the City of Murrieta, California (City).
Project Location
The Project site is generally located north of Clinton Keith Road and east of Mitchell Road in the City of Murrieta, County of Riverside. The Project site encompasses approximately 5.24 acres and is currently vacant. The Project site is approximately 0.3 mile west of Interstate 215 (I -215) and approximately 2.7 miles northeast of Interstate 15 (I-15).
Project Description
The proposed Project assumes the subdivision of approximately 5.24 acres into three parcels to allow for the development of the two southernmost parcels for commercial uses. Therefore, the development area assumed in this analysis is 2.3 acres. The proposed Project is a commercial development composed of a convenience store and gasoline station, automated car wash, and drive-thru coffee store; refer to Exhibit 1: Site Plan.
Convenience Store and Gasoline Station
The convenience store would consist of approximately 3,700 square feet (sf), generally located on the northwestern portion of the Project site. The gas station would include 12 fueling pumps, located to the south of the convenience store.
Car Wash
The approximate 1,458 -sf automated drive -thru car wash would be located directly north of the convenience store. The car wash would include a conveyor wash tunnel with one vacuum and one dryer system. Overall, the car wash is anticipated to consume approximately 150,000 gallons of water per year.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Drive-thru Coffee Store
The proposed drive-thru coffee store would consist of approximately 886 square feet. The coffee store would be located on the southeastern portion of the Project site. The drive- thru entrance would be located to the northeast of the building and the drive -thru exit would be located on the western side of the building. An approximate 336 square foot outdoo r seating area would be situated to the east of the coffee store.
Project Parking and Circulation
The Project would provide 33 parking stalls, with vehicle parking located throughout the Project site. The property owner has an existing reciprocal access agreement with the property owner to the east of the Project site (the location of the Del Taco restaurant). Vehicular access for the P roject site would be provided via one existing driveway on Clinton Keith Road associated with the Del Taco restaurant east of the Project site that would continue to be a right- in-right-out only driveway; one proposed dri veway on Clinton Keith Road; one proposed driveway on Mitchell Road; and one proposed driveway on Sierra Lane.
The proposed driveway on Clinton Keith Road would be an “Entrance Only” driveway. The proposed driveways on Mitchell Road and Sierra Lane would be full access driveways. All proposed driveways would be unsignalized.
Project Construction
Construction of the proposed Project is expected to commence in 2024 with a construction duration of approximately 12 months and would be completed in one phase. Total grading for the proposed Project is estimated to require approximately 12,252 cubic yards of cut and approximately 12,252 cubic yards of fill; earthwork is expected to balance on site.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Exhibit 1: Site Plan
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Noise Background
Sound is technically described in terms of amplitude (loudness) and frequency (pitch). The standard unit of sound amplitude measurement is the decibel (dB). The decibel scale is a logarithmic scale that describes the physical intensity of the pressure vibrations that make up any sound. The pitch of the sound is related to the frequency of the pressure vibration. Since the human ear is not equally sensitive to a given sound level at all frequencies, a special frequency -dependent rating scale has been devised to relate noise to human sensitivity. The A -weighted decibel scale (dBA) provides this compensation by discriminating against frequencies in a manner approximating the sensitivity of the human ear.
Noise, on the other hand, is typically defined as unwanted sound. A typical noise environment consists of a base of steady ambient noise that is the sum of various distant and indistinguishable noise sources. The sound from individual local sources is superimposed on this background noise . These can vary from an occasional aircraft or train passing by to virtually continuous noise from traffic on a major highway.
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 that the effect of noise on people is largely dependent on the total acoustical energy content of the noise as well as the time of day when the noise occurs. Most commonly, environmental sounds are described in terms of L eq that has the same
acoustical energy as the summation of all the time-varying events. While the equivalent continuous sound level (Leq) represents the continuous sound pressure level over a given period; the Day-Night Sound level (Ldn) is a 24-hour average Leq with a 10 dBA “weighting” added to noise during the hours of 10:00 p.m. to 7:00 a.m. to account for noise sensitivity in the nighttime. The Community Noise Equivalent Level (CNEL) is a 24-hour average Leq with a 10-dBA weighting added to noise during the hours of 10:00 p.m. to 7:00 a.m. and an additional 5 dBA weighting during the hours of 7:00 p.m. to 10:00 p.m. to account for noise sensitivity in the evening and nighttime.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Regulatory Setting
State
California Government Code
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 Sta te 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 CNEL and “conditionally acceptable” up to 70 CNEL. Multiple-family residential uses are “normally acceptable” up to 65 CNEL and “conditionally acceptable” up to 70 CNEL. Schools, libraries, and churches are “normally acceptable” up to 70 CNEL, as are office buildings and business, commercial, and professional uses.
Title 24 – Building Code
The State’s noise insulation standards are codified in the California Code of Regulations, Title 24: Part 1, Building Standards Administrative Code, and Part 2, California Building Code. These noise standards are applied to new construction in California for interior noise compatibility from exterior noise sources. The regulations specify that acoustical studies must be prepared when noise -sensitive structures, such as residential buildings, schools, or hospitals, are located near major transportation noise sources, and where such noise sources create an exterior noise level of 65 dBA CNEL or higher. Acoustical studies that accompany building plans must demonstrate that the structure has been designed to limit interior noise in habitable rooms to acceptable noise levels. For new multi- family residential buildings, the acceptable interior noise limit for new construction is 45 dBA CNEL.
Regional
City of Murrieta General Plan
The General Plan Noise Element contains noise and land use compatibility standards for various land uses throughout the City; see Table 1: Land Use Compatibility for Community Noise Environments . The City uses these standards and criteria in the land use planning process to reduce future noise and land use incompatibilities. The standards shown in Table 1 are the primary tool that allows the City to ensure integrated planning for compatibility between land uses and outdoor noise.
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Table 1: Land Use Compatibility for Community Noise Environments Land Use Category
Community Noise Exposure (CNEL)
Normally
Acceptable
Conditionally
Acceptable
Normally
unacceptable
Clearly
Unacceptable
Residential-Low Density, Single-
Family, Duplex, Mobile Homes 50-60 55-70 70-75 75-85
Residential – Multiple Family 50-65 60-70 70-75 70-85
Transient Lodging – Motel, Hotels 50-65 60-70 70-80 80-85 Schools, Libraries, Churches,
Hospitals, Nursing Homes 50-70 60-70 70-80 80-85
Auditoriums, Concert Halls,
Amphitheaters NA 50-70 NA 65-85
Sports Arenas, Outdoor Spectator
Sports NA 50-75 NA 70-85
Playgrounds, Neighborhood Parks 50-70 NA 67.5-77.5 72.5-85 Golf Courses, Riding Stables, Water
Recreation, Cemeteries 50-70 NA 70-80 80-85
Office Buildings, Business Commercial
and Professional 50-70 67.5-77.5 75-85 NA
Industrial, Manufacturing, Utilities,
Agriculture 50-75 70-80 75-85 NA
CNEL = community noise equivalent level; NA = not applicable NORMALLY ACCEPTABLE: Specified land use is satisfactory, based upon the assumption that any buildings involved are of normal conventional construction, without any special noise insulation requirements.
CONDITIONALLY ACCEPTABLE: New construction or development should be undertaken only after a detailed analysis of the noise reduction requirements is made and needed noise insulation features have been included in the design. Conventional construction, but with closed windows and fresh air supply systems or air conditioning, will normally suffice.
NORMALLY UNACCEPTABLE: New construction or development should be discouraged. If new construction or development does proceed, a detailed analysis of the noise reduction requirements must be made and needed noise-insulation features must be included in the design.
CLEARLY UNACCEPTABLE: New construction or development should generally not be undertaken.
Source: City of Murrieta, City of Murrieta General Plan 2035, Table 11-2: Land Use Compatibility for Community Noise Environments.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
The Noise Element also contains the City’s exterior and interior noise standards; see Table 2: Exterior and Interior Noise Limits.
Table 2: City of Murrieta Exterior and Interior Noise Limits Noise Zone Land Use (Receptor Property) Time Period Allowed Exterior Noise Level (dBA)
Exterior Noise Limits a
I Noise-sensitive area Anytime 45
II
Residential properties
10:00 p.m. to 7:00 a.m. 45
7:00 a.m. to 10:00 p.m. 50
Residential properties within 500
feet of a kennel(s) 7:00 a.m. to 10:00 p.m. 70
III Commercial properties
10:00 p.m. to 7:00 a.m. 55
7:00 a.m. to 10:00 p.m. 60
IV Industrial properties Anytime 70
Interior Noise Limits
All noise zones Multi-family residential
10:00 p.m. to 7:00 a.m. 40
7:00 a.m. to 10:00 p.m. 45
a. Murrieta Municipal Code Section 16.30.090.B states the following:
B. Noise Standards. No person shall operate or cause to be operated. any source of sound at any location within the city or allow the creation of any noise on property owned, leased, occupied or otherwise controlled by a person that causes the noise level, when measured on any other property to exceed the following exterior noise standards:
1. Standard No. 1. Standard No. 1 shall be the exterior noise level which shall not be exceeded for a cumulative period of more than thirty (30) minutes in any hour. Standard No. 1 may be the applicable noise level from Table 3 -6 (Table 2) above.
2. Standard No. 2. Standard No. 2 shall be the exterior noise level which shall not be exceeded for a cumulative period of more than fifteen (15) minutes in any hour. Standard No. 2 shall be the applicable noise level from Table 3 -6 (Table 2) above, plus five dB.
3. Standard No. 3. Standard No. 3 shall be the exterior noise level which shall not be exceeded for a cumulative period of more than five minutes in any hour. Standard No. 3 shall be the applicable noise level from Table 3-6 (Table 2) above plus ten dB.
4. Standard No. 4. Standard No. 4 shall be the exterior noise level which shall not be exceeded for a cumulative period of more than one minute in any hour. Standard No. 4 shall be the applicable noise level from Table 3 -6 (Table 2) above plus fifteen (15) dB.
5. Standard No. 5. Standard No. 5 shall be the exterior noise level which shall not be exceeded for any period of time.
Standard No. 5 shall be the applicable noise level from Table 3-6 (Table 2) above plus twenty (20) dB.
Source: City of Murrieta, City of Murrieta General Plan 2035, Table 11-4: City of Murrieta Exterior and Interior Noise Limits; and City of Murrieta, Murrieta, California Municipal Code, Sections 16.30.090 and 16.30.100.
City of Murrieta Municipal Code
Section 16.30 (Noise) of the Murrieta Municipal Code (MMC) establishes standards to protect the health, safety, and welfare of those living and working in the City and to implement policies of the General Plan Noise Element.
MMC Section 16.30.130 regulates construction noise. MMC Section 16.30.130 prohibits noise generated by construction activities between the hours of 8:00 p.m. and 7:00 a.m. and on Sundays and holidays. In
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
addition, construction activities in accordance with MMC Section 16.30.130 shall be conducted in a manner that the maximum noise levels at the affected structures will not exceed those listed in Table 3:
City of Murrieta Construction Noise Standards . Construction noise at business structures (i.e., commercial/business receptors) is also limited to a maximum of 85 dBA. The MMC establishes operational noise standards for various land uses; see Table 1 above. Further, MMC Section 16.30.130(I) limits the operation of air conditioning or refrigeration equipment in a manner that exceeds the following sound levels in Table 4: City of Murrieta Residential Air Conditioning and Refrigeration Equipment Noise Standards.
Table 3: City of Murrieta Construction Noise Standards
Single-Family Residential Multi-Family
Residential Commercial
Mobile Equipment
Daily, except Sundays and holidays,
7:00 a.m. to 8:00 p.m. 75 dBA 80 dBA 85 dBA
Daily, except Sundays and holidays,
8:00 p.m. to 7:00 a.m. 60 dBA 64 dBA 70 dBA
Stationary Equipment
Daily, except Sundays and holidays,
7:00 a.m. to 8:00 p.m. 60 dBA 65 dBA 70 dBA
Daily, except Sundays and holidays,
8:00 p.m. to 7:00 a.m. 50 dBA 55 dBA 60 dBA
Source: City of Murrieta, Murrieta, California Municipal Code, Section 16.30.130(A).
Table 4: City of Murrieta Residential Air Conditioning and Refrigeration Equipment Noise Standards Measurement Location Maximum Noise Level (dBA)
Any point on neighboring property line, five feet above grade level, no closer than three feet from any wall. 55
Center of neighboring patio, five feet above grade level, no closer than three feet from any wall. 50
Outside the neighboring living area window nearest the
equipment location, not more than three feet from the window opening, but at least three feet from any other surface. 50 Source: City of Murrieta, Murrieta, California Municipal Code, Section 16.30.130(I).
Existing Setting
The Project site is impacted by various noise sources. Mobile sources of noise, including traffic along Clinton Keith Road to the south and Mitchell Road to the west are the most common and prominent sources of noise in the Project area. The primary sources of stationary noise near the Project site include parking lot noise at the nearby commercial properties, mechanical equipment (e.g., heating, ventilation, and air conditioning [HVAC] units) operating at the nearby commercial and residential uses, and other urban-related activities (e.g., idling cars/trucks, pedestrians, car radios and music playing, dogs barking, etc.). The noise associated with these sources may represent a single -event noise occurrence or short- term noise.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Noise Measurements
To quantify existing ambient noise levels in the Project area, Kimley-Horn conducted four short-term noise measurements on November 15, 2022, see Appendix A: Nosie Data. The noise measurement sites were representative of typical existing noise exposure within and immediately adjacent to the Project site, see Exhibit 2: Noise Measurement Locations. The 10-minute measurements were taken between 1:30 p.m. and 2:39 p.m. Short-term L
eq measurements are considered representative of the noise levels throughout the day. The average noise levels and sources of noise measured at each location are listed in Table 5:
Existing Noise Measurements.
Table 5: Existing Noise Measurements
Site Location Leq
(dBA)
Lmin
(dBA)
Lmax
(dBA) Time
1 Adjacent to Mitchell Place Apartments, along Mitchell Road to the west of the Project site. 60.4 45.9 71.3 1:30 p.m.
2 Southwest corner of Clinton Keith Road and Mitchell Road intersection. 71.2 54.2 80.7 1:43 p.m.
3 Adjacent to residential uses along Clinton Keith Road, to the south of the Project site. 76.9 52.2 85.6 1:55 p.m.
4 Adjacent to residential uses along Sierra Lane, to the north of the Project site. 58.4 45.8 75.7 2:12 p.m.
5 In commercial parking lot directly east of the Project site. 55.8 47.2 69.0 2:29 p.m.
Source: Noise measurements taken by Kimley-Horn and Associates, November 15, 2022. See Appendix A for noise measurement results.
Sensitive Receptors
Noise exposure standards and guidelines for various types of land uses reflect the varying noise sensitivities associated with each of these uses. Residences, hospitals, schools, guest lodging, libraries, and churches are treated as the most sensitive to noise intrusion and therefore have more stringent noise exposure targets than do other uses, such as manufacturing or agricultural uses that are not subject to impacts such as sleep disturbance. Sensitive receptors near the Project site are shown in Table 6: Sensitive Receptors.
Table 6: Sensitive Receptors
Receptor Description Distance and Direction from the Project Site1 Multi-family residential 375 feet to the north
Single-family residential 132 feet to the south
Multi-family residential 95 feet to the west
Antelope Hills Elementary School 470 feet to the south
The Linden at Murrieta Assisted Living 1,780 feet to the west
1. Distances are measured from the Project site boundary to the sensitive receptor property line.
Source: Google Earth, 2022
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Exhibit 2: Noise Measurement Locations
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Noise Impacts
Construction Noise
Construction noise typically occurs intermittently and varies depending on the nature or phase of construction (e.g., land clearing, grading, excavation, paving). Noise generated by construction equipment, including earth movers, material handlers, and por table generators, can reach high levels.
During construction, exterior noise levels could affect the buildings near the construction site.
Construction activities would include grading/infrastructure improvements, building construction, paving, and architectural coating applications. Such activities may require graders, dozers, and tractors/loaders/backhoes during grading; forklifts, generator sets, tractors/loaders/backhoes, and welders during building construction; pavers, rollers, mixers, tractors/loaders/backhoes, and paving equipment during paving; and air compressors during architectural coating applications. Typical operating cycles for these types of construction equipment may involve 1 or 2 minutes of full power operation followed by 3 to 4 minutes at lower power settings. Other primary sources of acoustical disturbance would be random incidents, which would last less than one minute (such as dropping large pieces of equipment or the hydraulic movement of machinery lifts). Noise generated by construction equipment, including earth movers, material handlers, and portable generators, can reach high levels. The grading phase of Project construction tends to be the shortest in duration and create the highest construction noise levels due to the operation of heavy equipment required to complete these activities. It should be noted that only a limited amount of equipment can operate near a given location at a particular time. Typical noise levels associated with individual construction equipment are listed in Table 7: Typical Construction Noise Levels.
As indicated in Table 7, construction noise levels would be noticeable at the nearby residential uses and other properties in the Project vicinity. However, actual construction -related noise activities would be lower than the conservative levels shown in Table 7 and would cease upon completion of construction.
Due to the variability of construction activities and equipment for the P roject, overall construction noise levels would be intermittent and would fluctuate over time. In addition, the noise levels above assume that construction noise is constant, when, in fact, construction activities and associated noise levels would fluctuate and generally be brief and sporadic, depending on the type, intensity, and location of construction activities.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Table 7: Typical Construction Noise Levels
Equipment Typical Noise Level (dBA) at 50 feet from Source Air Compressor 80
Backhoe 80
Compactor 82
Concrete Mixer 85
Concrete Pump 82
Concrete Vibrator 76
Crane, Mobile 83
Dozer 85
Generator 82
Grader 85
Impact Wrench 85
Jack Hammer 88
Loader 80
Paver 80
Pneumatic Tool 85
Pump 77
Roller 85
Saw 76
Scraper 85
Shovel 82
Truck 84
Source: Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, September 2018.
The nearest noise- sensitive receptors to the P roject site include multi -family residences located approximately 375 feet to the north and 95 feet to the west, as well as single -family residences located approximately 132 feet to the south . The proposed P roject may expose these sensitive receptors to elevated noise levels during Project construction. However, it is acknowledged that construction activities would occur throughout the Project site and would not be concentrated at the point closest to the sensitive receptors.
The noise levels calculated in Table 8: Project Construction Noise Levels , show the P roject’s estimated exterior construction noise levels without accounting for attenuation from existing physical barriers. This analysis assumes that all construction equipment would operate simultaneously at a center of the construction area in accordance with methodologies from the Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment Manual (September 2018) (FTA Transit Noise and Vibration Manual).
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
Table 8: Project Construction Noise Levels
Construction
Phase
Receptor Location Worst Case
Modeled
Exterior Noise
Level (dBA Leq)
Noise
Threshold
(dBA Leq)2
Exceeded?
Land Use Direction
Distance to
Project Site
Center (feet)1
Grading/
Infrastructure
Improvements
Multi-Family
Residential North 508 65.7 80 No
Single-Family
Residential South 265 71.4 75 No
Multi-Family
Residential West 290 70.6 80 No
Commercial West 195 74.1 85 No
Building
Construction
Multi-Family
Residential North 508 63.4 80 No
Single-Family
Residential South 265 69.1 75 No
Multi-Family
Residential West 290 68.3 80 No
Commercial West 195 71.8 85 No
Paving
Multi-Family
Residential North 508 64.5 80 No
Single-Family
Residential South 265 70.2 75 No
Multi-Family
Residential West 290 69.4 80 No
Commercial West 195 72.8 85 No
Architectural
Coating
Multi-Family
Residential North 508 53.6 80 No
Single-Family
Residential South 265 59.2 75 No
Multi-Family
Residential West 290 58.5 80 No
Commercial West 195 61.9 85 No
Building
Construction/
Paving/
Architectural
Coating
Multi-Family
Residential North 508 67.2 80 No
Single-Family
Residential South 265 72.9 75 No
Multi-Family
Residential West 290 72.1 80 No
Commercial West 195 75.5 85 No
1. Per the methodology described in the FTA Transit Noise and Vibration Impact Assessment Manual (September 2018), distances are measured from the nearby buildings to the center of the Project construction site. Therefore, distance may not match those identified in the context, which are measured from the property line.
2. The City employs construction noise standards of 75 dBA for single-family residential uses, 80 dBA for multi-family residential uses, and 85 dBA for commercial uses as outlined in MMC Section 16.30.130 and Table 3.
Source: Federal Highway Administration, Roadway Construction Noise Model, 2006. See Appendix A for noise modeling results.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
MMC Section 16.30.130 has established quantitative construction noise standards of 75 dBA for single- family residential uses, 80 dBA for multi-family residential uses, and 85 dBA for commercial/nonresidential uses during daytime hours (between 7:00 a.m. to 8:00 p.m.). As shown in Table 8, noise levels at the nearest sensitive receptors could reach a maximum of 72.9 dBA at the property line of the n earest sensitive receptor (the single- family residential uses to the south ) during the overlapping building construction, paving, and architectural coating phases. Therefore, construction noise levels would not exceed the City’s construction noise standards. While ambient noise levels in the P roject vicinity would temporarily increase during construction activities, construction noise would be acoustically dispersed throughout the Project site and not concentrated in one area near surrounding sensitive uses. Therefore, construction noise would not substantially increase ambient noise levels in exceedance of any City standards. Construction-related noise impacts would be less than significant in this regard.
Operational Noise
On-Site Operations
Implementation of the proposed Project would create new sources of noise in the Project vicinity. The major noise sources associated with the Project that would potentially impact existing nearby residences include stationary noise equipment (i.e., air con ditioners, car wash vacuum and dryer system, etc.); parking areas (i.e., car door slamming, car radios, engine start -up, and car pass-by); truck deliveries and trash/recycling pickups; drive -thru operations; and off -site traffic noise. A discussion of each of th ese Project noise sources is provided below.
Mechanical Equipment. Potential stationary noise sources related to long -term operation of the Project would include mechanical equipment. Mechanical equipment (e.g., heating ventilation and air conditioning [HVAC] equipment) typically generates noise levels of approximately 52 dBA at 50 feet. 1 The
Project would include HVAC units located on the rooftop of the proposed convenience store and coffee shop buildings and the units would be located behind a parapet. HVAC units would be located as close as 143 feet from the property line of the multi-family residences to the west and as close as 210 feet from the single-family residences to the south. Based upon the Inverse Square Law, sound levels decrease by 6 dBA for each doubling of distance from the source. As a result, HVAC noise levels w ould attenuate by distance to approximately 42.9 dBA at the residences to the west and 39.5 dBA at the residences to the south. The parapets would also provide additional attenuation, which would reduce HVAC noise levels to
34.9 dBA and 31.5 dBA to the west and south, respectively. Therefore, HVAC noise would not exceed the City’s daytime (50 dBA) or nighttime (45 dBA) exterior noise standards for residential uses. Impacts from mechanical equipment would be less than significant.
Car Wash Operations. The automated drive-thru car wash would include a conveyor wash tunnel with one vacuum and one dryer system and would not include speakers or intercoms. Car wash operations would occur during daytime hours ( 7:00 a.m. to 9 :00 p.m.). The Project would utilize one AquaDri FS-40 dryer system and a standard car wash vacuum unit. The AquaDri FS-40 dryer system generates 89 dBA at a distance of 10 feet from the source . Because the drying cycle represents a small portion of the overall
1 Elliott H. Berger, Rick Neitzel, and Cynthia A. Kladden, Noise Navigator Sound Level Database with Over 1700 Measurement Values, 2015.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
wash, the dryers are anticipated to operate for no more than 30 minutes during any given hour. The calculated Hourly Leq given 30 minute usage of the dryer cycle at the exit would be 86 dBA at a reference distance of 10 feet. A standard car wash vacuum unit generates 72 dBA at a distance of 10 feet. The nearest sensitive receptors are the multi-family residential uses to the west and the single -family residential uses to the south. The dryers would be located within the eastern portion of the car wash and the car wash vacuum would be located along Clinton Keith Road; refer to Appendix A for dryer system and vacuum locations. Table 9: Car Wash Noise Levels shows the combined car wash noise level at the nearest sensitive receptors. As shown in Table 9, car wash operations would generate a combined noise level of 48.6 dBA at the multi-family residential uses to the west and 49.1 dBA at the single -family residential uses to the south, which would not exceed the City’s daytime (7:00 a.m. to 10:00 p.m.) exterior noise standard (50 dBA) for residential uses. As the car wash would not operate after9:00 p.m. and would not exceed the City’s nighttime (10:00 p.m. to 7:00 a.m.) noise standards. Therefore, noise levels generated by car wash operations would be less than significant.
Table 9: Car Wash Noise Levels
Receptor Source Reference
Noise Level1
Reference
Distance
Nearest
Receptor
Distance from
Source (feet)2
Building Row
Attenuation3
Modeled
Exterior Noise
Level at
Nearest
Sensitive
Receptor (dBA)
Multi-
family
Residential
Uses to the
West
Dryers 86 dBA 10 Feet 238 Feet 15 43.5
Vacuum 72 dBA 10 Feet 178 Feet NA 47.0
Car Wash Combined Noise Level 48.6
Noise Threshold (dBA)4 50
Threshold Exceeded? No
Single-
family
Residential
Uses to the
South
Dryers 86 dBA 10 Feet 369 Feet 15 39.6
Vacuum 72 dBA 10 Feet 148 Feet NA 48.6
Car Wash Combined Noise Level 49.1
Noise Threshold (dBA)4 50
Threshold Exceeded? No
NA = Not Applicable
1. Noise level specifications for the dryer system and vacuum were provided by the Applicant. Refer to Appendix A.
2. The nearest sensitive receptors are the multi-family residential uses to the west.
3. Building row attenuation assumes partial obstruction as the dryers would be inside the car wash building. Refer to Appendix A for barrier calculations.
4. The car wash would operate during daytime hours, between 7:00 a.m. to 9:00 p.m. Therefore, the City’s daytime exterior noise standard for residential uses (50 dBA) was applied.
Drive-Thru Operations. The proposed drive-thru coffee shop would not utilize a drive-thru speakerphone.
Instead, staff would take orders with tablets at various points throughout the drive-thru queue. Sound levels of speech typically range from 33 dBA at 50 feet for normal speech to 50 dBA at 50 feet for very loud speech.
2 The nearest sensitive receptors ( single-family residential uses to the south) would be
2 Elliott H. Berger, Rick Neitzel, and Cynthia A. Kladden. Noise Navigator Sound Level Database with Over 1700 Measurement Values, 2015.
kimley-horn.com 1100 W. Town and Country Road, Suite 700, Orange, CA 92868 714 939 1030
located approximately 210 feet, and the sensitive receptors to the west would be 320 feet from the end of the drive-thru. At this distance, drive-thru operation noise levels would be approximately 37.5 dBA and
33.9 dBA at the south and the west, respectively. Therefore, drive-thru operations would not exceed the City’s daytime (50 dBA) or nighttime (45 dBA) exterior noise standards for residential uses and impacts would be less than significant.
Truck Deliveries and Trash/Recycling Collection. It is anticipated that the proposed Project would involve occasional deliveries (i.e., deliveries of gasoline, diesel, and supplies for the convenience store and coffee shop) and weekly trash/recycling collection from slow-moving trucks during daylight hours. However, this analysis considers potential nighttime truck deliveries to provide a conservative analysis. The primary noise source associated with trucks are the air brakes, engine idling, back up alarms, engine ignition, and acceleration. Once the trucks have pulled in to the parking lot, they are unloaded using a hand cart, and most of that unloading noise would be contained within the truck trailer. It should be noted that per the California Code of Regulations, Title 13, Section 2485, trucks would be prohibited from idling more than five minutes.
Delivery truck noise levels were calculated for the P roject based on reference truck noise levels and the inverse square law of sound propagation. Truck unloading related noises would occur for brief periods during the delivery process. For example, air brake and backup alarm noises last a few seconds and idling would be limited to five minutes. Truck unloading would have the longest duration and would make up the majority of the time during each delivery event. Table 10: Delivery Truck Noise, provides the delivery truck noise levels at the Project property line near the closest sensitive receptors.
As shown in Table 10, the combined delivery truck noise levels would range from 32.8 to 43.4 dBA L eq at
the nearest sensitive receptors. Therefore, delivery truck noise levels would not exceed the City’s daytime (50 dBA) or nighttime (45 dBA) exterior noise standards for residential uses. Delivery times are currently unknown; however, Project noise levels would not exceed daytime or nighttime standards. In addition, truck deliveries and trash/recycle collection activities occur at the adjacent commercial uses under existing conditions, and traffic noise along Clinton Keith Road and Mitchell Road would act as a buffer from on -site truck noise levels. Therefore, potential noise impacts associated with deliveries and trash/recycling would be less than significant impact and no mitigation would be required.
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Table 10: Truck Delivery Noise
Sensitive
Receptor Source
Reference
Noise Level
(dBA)
Reference
Distance
(feet)
Distance to
Receptor
Property Line
(feet)
Noise Level at
Receptor
Property Line
(dBA Leq)
Daytime
Ambient Noise
Level
(dBA Leq)
Vendor and Convenience Store/Coffee Store Trucks
Single-Family
Residential
Uses to the
South6
Truck Pass-by (arrival, departure) 68 30 1501 16.1 76.9 Idle (arrival, departure) 70 25 3202 31.7 76.9
Truck Engine Ignition and Airbrakes 71 25 3202 6.1 76.9 Truck backup alarm 79 30 3202 21.7 76.9
Unloading 60 25 3202 23.8 76.9
Combined Noise Level (1-hour Leq) 3 -- -- 150-3201, 2 32.8 -- Multi-Family
Residential
Uses to the
West
Truck Pass-by (arrival, departure) 68 30 2502 18.6 60.4 Idle (arrival, departure) 70 25 2502 40.8 60.4
Truck Engine Ignition and Airbrakes 71 25 2502 15.2 60.4 Truck backup alarm 79 30 2502 30.8 60.4
Unloading 60 25 2502 33.0 60.4
Combined Noise Level (1-hour Leq) 3 -- -- 2502 41.9 -- Fueling Trucks
Single-Family
Residential
Uses to the
South6
Truck Pass-by (arrival, departure) 68 30 1784 14.5 76.9 Idle (arrival, departure) 70 25 1784 36.8 76.9
Truck Engine Ignition and Airbrakes 71 25 1784 11.2 76.9 Truck backup alarm 79 30 1783 26.8 76.9
Combined Noise Level (1-hour Leq) 5 -- -- 1784 37.2 --
Multi-Family
Residential
Uses to the
West
Truck Pass-by (arrival, departure) 68 30 2204 20.7 60.4 Idle (arrival, departure) 70 25 2204 42.9 60.4
Truck Engine Ignition and Airbrakes 71 25 2204 17.3 60.4 Truck backup alarm 79 30 2204 32.9 60.4
Combined Noise Level (1-hour Leq) 5 -- -- 2204 43.4 60.4
1. This distance represents the closet point of the drive aisle to the property line of the residences.
2. This is the distance measured from the proposed loading/unloading area to the property line of the sensitive receptors.
3. As the delivery truck noise consists primarily of several brief noise events, each noise level was averaged to determine the 1-hour Leq noise level.
4. This is the distance measured from the proposed re-fueling area to the property line of the sensitive receptors.
5. Noise levels calculated based on distance attenuation using the inverse-square law. As the delivery truck noise consists primarily of several brief noise events, each noise level was averaged to determine the 1-hour Leq noise level.
6. Residents Include a block wall barrier. Therefore, an 8 dBA reduction was applied. Attenuation per RCNM Appendix A.
Parking Lot Noise. The Project would provide 33 parking stalls, located throughout the Project site. Traffic associated with parking lots is typically not of sufficient volume to exceed community noise standards, which are based on a time -averaged scale such as the CNEL scale. The instantaneous maximum sound levels generated by a car door slamming, engine starting up, and car pass -bys range from 53 to 61 dBA.3 Conversations in parking areas may also be an annoyance to adjacent sensitive receptors. Sound levels of speech typically range from 33 dBA at 50 feet for normal speech to 50 dBA at 50 feet for very loud speech. 4 It should be noted that parking lot noises are instantaneous noise levels compared to noise standards in
3 Kariel, H. G., Noise in Rural Recreational Environments, Canadian Acoustics 19(5), 3-10, 1991. 4 Elliott H. Berger, Rick Neitzel, and Cynthia A. Kladden. Noise Navigator Sound Level Database with Over 1700 Measurement Values, 2015.
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the hourly Leq or 24-hour CNEL metrics, which are averaged over the entire duration of a time period. As a result, actual noise levels over time resulting from parking lot activities would be far lower than the reference levels identified above.
For the purpose of providing a conservative, quantitative estimate of the noise levels that would be generated from the vehicles entering and exiting the parking lot, the methodology recommended by FTA for the general assessment of stationary transit noise sources is used. Using the methodology, the Project’s peak hourly noise level that would be generated by the on -site parking levels was estimated using the following FTA equation for a parking lot:
L
eq(h) = SELref + 10 log (NA/1,000) – 35.6
Where:
Leq(h) = hourly Leq noise level at 50 feet
SELref = reference noise level for stationary noise source represented in sound exposure level (SEL) at 50 feet
NA = number of automobiles per hour
35.6 is a constant in the formula, calculated as 10 times the logarithm of the number of seconds in an hour
Based on the peak hour trip generation rates in the Focused Traffic Analysis for the Proposed Clinton Keith Road Project (Traffic Analysis), prepared by Kimley -Horn and Associates, Inc. (dated October 11, 2022), approximately 344 trips during peak hours would be made to the Project site each day. Using the FTA’s reference noise level of 92 dBA SEL
5 at 50 feet from the noise source, the Project’s highest peak hour vehicle trips would generate noise levels of approximately 51.8 dBA Leq at 50 feet from the parking lot.
The nearest parking spaces would be approximately 140 feet from the nearest noise -sensitive receptors (multi-family residential uses to the west). Based strictly on distance attenuation, parking lot noise at the nearest sensitive receptor (multi-family residential uses to the west) would be approximately 42.9 dBA, which is below the City’s daytime (50 dBA) and nighttime (45 dBA) exterior noise standards for residential uses. Therefore, noise impacts from parking lots would be less than significant.
Combined Operational Noise Levels . Project operational n oise was modeled with the SoundPLAN software. SoundPLAN allows computer simulations of noise situations, and creates noise contour maps using reference noise levels, topography, point and area noise sources, mobile noise sources, and intervening structures. Modeled noise levels are based on reference data. Noise levels at the nearest off- site properties and sensitive receptors surrounding the Project site were calculated using the input data described above.
Table 11: Noise Level Contributions shows the individual noise contributions from the various on -site sources at the sensitive receptors to the west and to the south. The modeled noise contours are shown in Exhibit 3: Project Daytime Noise Contours and Exhibit 5: Project Nighttime Noise Contours. The worst-
5 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, September 2018.
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case combined daytime noise levels would be 49.7 dBA at the receptors to the west and 48.8 dBA at the receptors to the south respectively. The worst- case combined nighttime noise levels would be 44.6 dBA and 43.9 dBA at the receptors to the west and south, respectively. Accounting for a 24 dBA exterior- to- interior attenuation factor, the interior noise levels generated by the combined operational noise sources would be approximately 21 dBA at the multi-family residential uses to the west and 20 dBA at the single- family residences to the south.6 Therefore, the combined operational noise levels would not exceed the City’s exterior daytime (50 dBA), exterior nighttime (45 dBA), or interior nighttime (40 dBA) 7 noise standards for residential uses.
Table 11: Noise Level Contributions
Source
Noise Level (dBA)
West Receptor South Receptor
7:00 a.m.
to 10:00 p.m.
10:00 p.m.
to 7:00 a.m.
7:00 a.m.
to 10:00 p.m.
10:00 p.m.
to 7:00 a.m.
Car Wash 39.7 NA 33.8 NA
Mechanical Equipment (HVAC) 39.7 39.7 35.1 35.1
Gas Station and Convenience Store 45.0 41.5 44.0 40.4
Drive-Thru/Walk-Up Window 42.9 42.9 41.6 41.6
Parking 39.8 30.3 39.6 33.9
Vacuum Space 41.3 NA 43.4 NA
HVAC = heating, ventilation, and air conditioning ; NA = not applicable (i.e., the noise source would not operate during the specified time)
1. The car wash would not operate during the 10:00 p.m. to 7:00 a.m. period.
6 U.S. Environmental Protection Agency, Protective Noise Levels (EPA 550/9-79-100), November 1979. 7 MMC Section 16.30.100, Interior Noise Standards for Multi-Family Residential.
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Exhibit 3: Project Daytime Noise Contours
Legend
Property Line
Receiver Point
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Exhibit 4: Project Nighttime Noise Contours
Legend
Property Line
Receiver Point
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Off-Site Traffic Noise
The proposed Project would result in additional traffic on adjacent roadways from daily activities, thereby increasing vehicular noise in the vicinity of existing and proposed land uses. A traffic noise level increase is considered substantial if:
• The “Opening Year With out Project” noise level exceed s the normally acceptable land use compatibility standards presented in Table 1 (60 dBA for residential and 77.5 for commercial) and the proposed project would increase this noise level by 3 dBA CNEL (barely noticeable in an exterior environment) or more.
Traffic noise levels for roadways primarily affected by the Project were calculated using the FHWA’s Highway Noise Prediction Model (FHWA-RD-77-108). Traffic noise modeling was conducted for conditions with and without the Project, based on traffic volumes obtained from the Traffic Analysis. The calculated traffic noise levels for the “Opening Year Without Project” and “Opening Year With Project” scenarios are compared in Table 12: Opening Year Traffic Noise Levels . As depicted in Table 12, under the “Openi ng Year Without Project” scenario, noise levels would range from approximately 48.2 dBA to 69.6 dBA, with the highest noise levels occurring along the Clinton Keith Road segment from Mitchell Road to McElwain Road. The “Opening Year With Project” scenario noise levels would range from approximately 48.2 dBA to 69.7 dBA, with the highest noise levels also occurring along the Clinton Keith Road segment from Mitchell Road to McElwain Road.
Table 12: Opening Year Traffic Noise Levels
Roadway Segment
Opening Year
Without Project
Opening Year
With Project Change Significant
Impacts ADT dBA CNEL1 ADT dBA CNEL1
Sierra Lane
Mitchell Road to McElwain Road 850 49.1 1,030 49.9 0.8 No Mitchell Road
North of Sierra Lane 420 48.2 420 48.2 0.0 No
Sierra Ln to Project Driveway 1,870 54.7 2,050 55.1 0.4 No Project Driveway to Clinton Keith Road 2,170 55.4 5,060 59.0 3.7 No South of Clinton Keith Road 2,180 51.7 2,360 52.1 0.3 No Clinton Keith Road
Greer Road to Mitchell Road 31,780 69.4 33,350 69.6 0.2 No Mitchell Road to McElwain Road 33,260 69.6 34,370 69.7 0.1 No ADT = average daily trips; dBA = A-weighted decibels; CNEL = community noise equivalent level.
1. Traffic noise levels are at 100 feet from the roadway centerline. The actual sound level at any receptor location is dependent upon such factors as the source-to-receptor distance and the presence of intervening structures, barriers, and topography.
Source: Based on traffic data within the Focused Traffic Analysis for the Proposed Clinton Keith Road Project (Traffic Analysis), prepared by Kimley-Horn and Associates, Inc. (dated October 11, 2022). Refer to Appendix A for traffic noise modeling assumptions and results.
As depicted in Table 12, the “Opening Year With Project ” scenario traffic noise levels would not exceed the 3.0 dBA increase significance threshold along any of the surrounding roadways, with the exception of the Mitchell Road segment from the Project Driveway to Clinton Keith Road . However, the noise level along this roadway segment would be 59.0 dBA, which would not exceed the normally acceptable land use compatibility standard for residential uses (60 dBA). Therefore, the Project would not exceed both the 3 dBA CNEL threshold and normally acceptable land use compatibility standards. As a result, the
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Project would not result in a perceptible increase in traffic noise levels and impacts would be less than significant.
Vibration Impacts
Project construction can generate varying degrees of groundborne vibration, depending on the construction procedure and the construction equipment used. Operation of construction equipment generates vibrations that spread through the ground and diminish in amplitude with distance from the source. The effect on buildings located near the construction site often varies depending on soil type, ground strata, and construction characteristics of the receiver building(s). The results from vibration can range from no perceptible effects at the lowest vibration levels, to low rumbling sounds and perceptible vibration at moderate levels, to slight damage at the highest levels. Ground -borne vibrations from construction activities rarely reach levels that damage structures.
The Federal Transit Administration (FTA) has published standard vibration velocities for construction equipment operations. In general, the FTA architectural damage criterion for continuous vibrations (i.e.,
0.20 inch/second) appears to be conservative. The types of construction vibration impact include human annoyance and building damage. Human annoyance occurs when construction vibration rises significantly above the threshold of human perception for extended periods. Building damage can be cosmetic or structural. Table 13: Typical Vibration Levels for Construction Equipment, lists vibration levels at 25 feet for typical construction equipment. Groundborne vibration generated by construction equipment spreads through the ground and diminishes in magnitude with increases in distance. As indicated in Table 13, based on FTA data, vibration velocities from typical heavy construction equipment operations that would be used during Project construction range from 0.003 to 0. 210 in/sec PPV at 25 feet from the source of activity.
Table 13: Typical Vibration Levels for Construction Equipment Equipment Approximate Peak Particle Velocity
at 25 Feet (inches/second)
Approximate Peak Particle Velocity
at 50 Feet (inches/second)
Vibratory compactor/roller 0.210 0.074
Large bulldozer 0.089 0.031
Loaded trucks 0.076 0.027
Jackhammer 0.035 0.012
Small bulldozer 0.003 0.001
1. Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, September 2018. Table 7-4.
2. Calculated using the following formula: PPV equip = PPVref x (25/D)1.5 where: PPV (equip) = the peak particle velocity in in/sec of the equipment adjusted for the distance PPV (ref) = the reference vibration level in in /sec from Table 7 -4 of the FTA Transit Noise and Vibration Impact Assessment Manual, September 2018.
D = the distance from the equipment to the receiver
The nearest structure to any construction activity is the commercial building located approximately 50 feet to the east of proposed construction activities. Vibration velocities from construction equipment would range from 0.00 1 to 0. 074 in/sec PPV at the nearest structure, which would not exceed the structural damage criteria (0.2 in/sec PPV) or human annoyance criteria (0.4 in/sec PPV); refer to Table
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13. It is also acknowledged that construction activities would occur throughout the Project site and would not be concentrated at the point closest to the nearest structure or sensitive receptor. Therefore, vibration impacts associated with the proposed Project would be less than significant.
Conclusion
Project implementation would result in less than significant short - and long- term noise and vibration impacts. No mitigation measures would be required. Therefore, the proposed Project would not result in significant effects related to noise and vibration.
Appendix A
Noise Data