HomeMy WebLinkAbout05-11-2016 PC Item 01 - 363 Santa Rosa Street (USE-2551-2015)
PLANNING COMMISSION AGENDA REPORT
SUBJECT: Review of a proposed new automatic car wash facility in the Tourist Commercial (C-T)
Zone
PROJECT ADDRESS: 363 Santa Rosa BY: Kyle Van Leeuwen, Planning Technician
Phone Number: 781-7091
e-mail: kvanleeuwen@slocity.org
VIA: Tyler Corey, Principal Planner
FILE NUMBER: USE-2551-2015 FROM: Xzandrea Fowler, Deputy Director
RECOMMENDATION: Adopt the draft resolution (Attachment 1) approving a use permit to allow a
car wash facility in the Tourist Commercial (C-T) zone, subject to findings and conditions.
SITE DATA
Address 363 Santa Rosa Street (Hwy 1)
Applicant SLO Wash Partners
Representative George Garcia, AIA
garcia architecture+design
Property Owner Benedix, Castro, Garris, January,
Winkes & Tartagalia
Zoning Tourist-Commercial (C-T)
General Plan Tourist Commercial
Environmental
Status
Categorically Exempt
(CEQA Guidelines §15332: In-Fill
Development Projects)
SUMMARY
The project applicant, SLO Wash Partners, has applied for a use permit to allow a car wash facility at
363 Santa Rosa Street. The proposed project will include the construction of an automatic car wash
tunnel, vacuum stations, and pay kiosk structure with a care taker unit located above. Operation of a car
wash is allowed in the Tourist-Commercial (C-T) Zone with the approval of a use permit by the
Planning Commission.
Meeting Date: May 11, 2016
Item Number: 1
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1.0 COMMISSION’S PURVIEW
The Planning Commission’s role is to review the use permit request in terms of its consistency with the
General Plan, Zoning Regulations, and applicable City standards.
2.0 PROJECT INFORMATION
2.1 Site Information/Setting
The project site is an approximately 1/2 acre parcel within the Tourist-Commercial (C-T) Zone. It is on
the southeast corner of Santa Rosa Street and Montalban Street, and currently has 2 driveway
approaches (curb cuts) off of Montalban and 2 approaches off of Santa Rosa. Santa Rosa is also
Highway 1 at this location and under State jurisdiction. The site itself does not have significant physical
or topographic features, and the only notable vegetation is a line of trees along the properties southern
border. This location was previously the site of a gasoline service station which was demolished in 2006.
Site Size 21,150 Square Feet
Present Use & Development Vacant Commercial Lot
Topography Relatively Flat
Access Montalban and Santa Rosa Streets
Surrounding Use/Zoning North: C-T (Commercial Uses: office/restaurant)
South: C-T (Commercial Uses: restaurant)
East: C-T (Commercial Uses: restaurant/retail)
West: C-T (Commercial Uses: residential)
The surrounding businesses include Taco Bell, Taco de Mexico, San Luis Ambulance, Lombard’s
Stereo, the May Firm injury lawyers, the Real Estate Office, San Luis Bail Bonds and Breakfast Buzz.
The subject property is also bordered by a seven unit apartment complex to the west, the Olive Branch
Apartments, which were built in the late 1960s.
2.2 Project Description
New Structures: The project proposes two new structures to be built on site. The first structure will hold
a conveyor-type car wash tunnel, car wash equipment room and customer restroom. This structure will
be located adjacent to the Santa Rosa Street Frontage. The second proposed structure will be located
near the western property line and will house the kiosk pay station on the ground floor with a caretaker’s
studio unit above.
Self-Service Vacuum Area: In the center of the lot, between the two new structures, is a parking area
equipped with seven self-service vacuum stanchions. The stanchions service the 12 parking spaces
provided in this area. This includes one ADA van accessible space with access to the equipment. This
does not including the parking space for the caretakers unit
Vehicle Path of Travel: Vehicles accessing the facility will enter from Montalban Street and will
proceed down a pair of queuing lanes to the pay kiosk. The queuing lanes are more than 60 feet long and
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can hold at least 3 cars in each of the two lanes leading up to the pay location. After the pay kiosk, cars
will continue across the southern edge of the property and turn into the car wash tunnel. The cars will
exit the tunnel and proceed to either the self-service vacuum area or the exit located where they entered
onto Montalban Street. Cars will also have the option of entering the facility and accessing the vacuum
stanchions only. The other existing driveway approaches (curb cuts) along Santa Rosa will be
abandoned.
Landscaping and Layout: Landscaping is prosed along the entire edge on the property with the exception
of the entrance/exit driveway. Additional landscaping is also proposed between the queuing line and
vacuum parking as well as at the beginning and end of the car wash tunnel. The site plan also calls out
the location of a trash enclosure, located near the entrance/exit of the facility. A designated parking
space for the caretaker’s unit is also provided. A monument sign near the street corner is also show on
plans. The layout of the project also takes into consideration the regional transportation plan as provided
by CalTrans with an increased setback for future right of way needs along Santa Rosa Street.
Operation: The proposed car wash facility will utilize eco-friendly water reclamation and recycle system
in order to maximize use of recycled water. The business is intended to operate 7 days a week, between
the hours of 7 am and 8 pm from April through September, and 7 am and 6 pm from October through
March.
3.0 PROJECT ANALYSIS
3.1 Consistency with the General Plan and Zoning Regulations
Appropriate Uses and Locations
The Land Use Element (LUE) of the General Plan describes the Tourist Commercial designation as
providing for uses that primarily serve the traveling public. These uses include hotels, motels,
restaurants, service stations, recreational uses, minor retail uses serving the needs of travelers, and public
and quasi-public uses (LUE Table 1). Tourist Commercial uses, as a basis for tourism, shall promote
San Luis Obispo as an attractive place for short-term stays, as well as an attractive destination for long-
term visitors, and should emphasize conference and visitor-serving facilities1. Locations of visitor-
serving uses are especially appropriate where such uses have already concentrated 2 (LUE 3.6.2). A car
1 LUE 3.6.1. Basis for Tourism. The City shall promote San Luis Obispo as an attractive place for short-term stays, as
well as an attractive destination for long-term visitors featuring its community character, natural qualities, historic
resources, and its educational and cultural facilities. The City should emphasize conference and visitor-serving facilities
which have a low impact upon the environment and upon existing land forms and landscapes, and which provide low-
impact visitor activities and low-impact means of transportation.
2 LUE 3.6.2. Locations. The City shall encourage integration of visitor-serving uses with other types of uses, including
overnight accommodations Downtown, near the airport, and near the train station; small-scale facilities (such as hostels
or bed-and-breakfast places) may be located in Medium-High Density Residential and High-Density Residential
Districts, where compatible. Visitor-serving uses are especially appropriate where such uses have already concentrated:
along upper Monterey Street; at the Madonna Road area; at certain freeway interchanges; and in the Downtown.
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wash may be allowed in the Tourist-Commercial (C-T) Zone if a use permit is granted by the Planning
Commission.
The proposed car wash, much like nearby gas stations, is not exclusively visitor-oriented. However, this
service is very useful to tourists traveling by automobile. It is conveniently located on Highway 1 (Santa
Rosa Street) and near the access street to Highway 101 South (Olive Street), and would serve the
traveling public at this location.
Noise Exposure
The Noise Element of the City’s General Plan lists residences and offices as noise sensitive land uses,
both of these uses are located on neighboring properties from the project site. The maximum acceptable
level of noise produced by the car wash is measured at the respective property line of the receiver. The
maximum noise exposure to these uses due to stationary noise sources is defined in table 2 of the Noise
Element (below).
Noise Element; Table 2. Maximum Noise Exposure for Noise-Sensitive Uses Due to Stationary Noise Sources
Additionally, the site is partially within the 70 dB noise contour and completely within the 65 dB noise
contour, as depicted in figure 4 of the General Plan’s Noise Element and described in Table 2 of the
City’s Noise Guide Book. These elevated noise levels are caused by Santa Rosa Street (Highway 1),
which affects the site and the surrounding properties. A car wash is not a noise-sensitive use according
to Figure 1 of the Noise Element (which lists noise sensitive uses), so mitigation of the noise exposure to
the car wash itself is not specifically required. However, the car wash will be an additional source of
noise, and the noise generated by the car wash in conjunction with noise levels produced by Santa Rosa
Street must be within allowable limits. The potential sources of noise from the car wash are described
below.
Dryer: As indicated in the acoustic analysis, the vehicle dryer unit at the end of the car wash
tunnel will be the main source of noise generated on the site. In this analysis two different types
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of drying units were analyzed to assess potential noise impacts (Attachment 5, Acoustic
Analysis, Pages 4 & 5). The louder of the two units measured at 78 dB directly in alignment with
the outlet, 50 feet from the source. This level is reduced when measured at varying angles from
the unit. The potential impacts to surrounding sensitive land uses has been addressed through
considerations in the design of the site plan, this includes locating the car wash tunnel with
drying unit adjacent to Santa Rosa Street, and the addition of the proposed “sound wing wall”,
greatly reduce the impacts to the residential use to the southwest.
Vacuums: The vacuum system used in the central parking area will be another source of noise.
The individual vacuum stanchions are all connected to a centralized unit that provides suction for
all hoses. The fan for this unit will be located within the concrete equipment enclosure next to
the car wash tunnel. This shielding will reduce the impact of vacuum noise and, as discussed in
the acoustic analysis, will be below the level of ambient noise on the site. The ambient noise
level at this location is 65 dB and the noise created by the unit without the concrete screening is
55 dB when at full operation and measured at 50 feet from the source.
The acoustic analysis provided by the applicant (Attachment 5), assesses the potential noise impacts on
existing uses surrounding the car wash (adjacent residential units to the southwest and the office use
across Montalban Street to the North). In areas recognized to have higher ambient noise levels, the
municipal code allows for an increase in the maximum allowed level of noise exposure; adjusted in 5 dB
increments. In this instance, the maximum noise level is adjusted to 60 dB (Residential Use) and 75 dB
(Office Use) due to the proximity to Santa Rosa Street. The acoustic analysis concludes that the noise
levels that would be created by the car wash are within the allowable limits, when those limits are
adjusted to reflect the level of ambient noise (see Table 1 below). While the noise levels produced by the
car wash would not exceed City thresholds, it would be an additional source of noise for neighboring
residences and businesses.
Table 1: Allowable Noise Levels and Predicted Level Produced by Project (as measured at property line of use)
4.0 CONCLUSION
The proposed car wash, subject to the recommended conditions of approval, can be established and
maintained without being detrimental to health, safety or welfare of persons working or living on site or
Noise Level Measurement Residential Use (dB) Office Use (dB)
Noise Element Hourly Level (equivalent) 50 50
Noise Element Maximum Level 70 70
Allowable Level, adjusted for ambient noise (Muni Code) 60 75
Car wash Produced Hourly Level (equivalent) 51 69
Car Wash Produced Maximum Level 54 72
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within the vicinity. The proposed use is appropriate at this location within the Tourist Commercial zone,
as it will serve both auto-oriented tourists and permanent residents. The proposed design of the project
will keep noise exposure levels within permitted limits.
5.0 REVIEW AND COMMENT
Project plans were routed to several departments for review, and various comments were submitted in
response. Those comments were incorporated into conditions and code requirements, as appropriate.
6.0 ALTERNATIVES
6.1 Deny the project. An action denying the application should include findings that cite the basis for
denial and should reference inconsistency with the General Plan, Zoning Regulations, Municipal
Code or other policy documents.
6.2 The Planning Commission may continue review of the project, if more information is needed.
Direction should be given to staff and the applicant.
7.0 ATTACHMENTS
1. Draft Resolution
2. Vicinity Map
3. Project Statement
4. Project Plans (Reduced Size)
5. Acoustic Analysis, prepared by David Dubbink Associates
Included in Commission Member Portfolio: Project Plans (Full Size)
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RESOLUTION NO. PC-####-16
A RESOLUTION OF THE SAN LUIS OBISPO PLANNING COMMISSION
GRANTING A USE PERMIT ALLOWING THE ESTABLISHMENT AND OPERATION
OF A CAR WASH IN THE TOURIST COMMERCIAL (C-T) ZONE
AND DETERMINING THAT THE PROJECT IS EXEMPT FROM THE PROVISIONS
OF THE CALIFORNIA ENVIRONMENTAL QUALITY ACT, AS REPRESENTED IN
THE STAFF REPORT AND ATTACHMENTS DATED MAY 11, 2016
(363 SANTA ROSA, USE-2551-2015)
WHEREAS, the Planning Commission of the City of San Luis Obispo conducted a
public hearing in the Council Chamber of City Hall, 990 Palm Street, San Luis Obispo,
California, on May 11, 2016, pursuant to a proceeding instituted under application USE-2551-
2016, SLO Wash Partners, applicant; and
WHEREAS, notices of said public hearing were made at the time and in the manner
required by law; and
WHEREAS, the Planning Commission has duly considered all evidence, including the
testimony of the applicant, interested parties, and evaluation and recommendations by staff
presented at said hearing.
NOW, THEREFORE, BE IT RESOLVED by the Planning Commission of the City of
San Luis Obispo as follows:
SECTION 1. Findings. Based upon all the evidence, the Commission makes the
following findings:
1. The proposed project will not be detrimental to the health, safety, or welfare of those
working or residing in the vicinity since the proposed project is consistent with the site’s
zoning and property development standards and will be subject to conformance with all
applicable building, fire, and safety codes.
2. The proposed project is consistent with General Plan policies applicable to the Tourist
Commercial land use designation because the site is located on Highway 1 (Santa Rosa
Street) and near the access street to Highway 101 South (Olive Street), and the proposed car
wash use will serve the traveling public at this location.
3. As conditioned, the proposed project is consistent with City policies related to noise exposure
levels because, due to the design of the proposed project, noise generating equipment is
located away from the adjacent residential use and, as confirmed by the acoustic analysis
prepared by David Dubbink Associates, anticipated noise levels are within all City standards.
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Resolution No. PC ####-16 Page 2
USE-2551-2015 (363 Santa Rosa Street)
SECTION 2. Environmental Review The project is categorically exempt from the
provisions of the California Environmental Quality Act (CEQA), as it is an in-fill development
project, as described in §15332 of the CEQA Guidelines.
SECTION 3. Action. The Commission hereby approves a use permit allowing the
establishment and operation of a car wash within the Tourist-Commercial (C-T) Zone, at 363
Santa Rosa Street, subject to the following conditions:
Planning
1. Conformance to Plans: Final project design and construction drawings submitted for
construction permits shall be in substantial compliance with the project plans approved by
the Planning Commission. A separate, full-size sheet shall be included in working drawings
that lists all conditions and code requirements of project approval listed as sheet number 2.
Reference shall be made in the margin of listed items as to where in plans requirements are
addressed. Any change to approved design, colors, materials, landscaping, or other
conditions of approval must be approved by the Director, Architectural Review Commission,
or Planning Commission, as deemed appropriate.
2. Architectural Review: The project shall obtain approval from the City’s Architectural
Review Commission prior to submitting an application for construction permits.
3. Exterior Lighting: Plans submitted for construction permits shall include a photometric plan
and sufficient information to show compliance with Night Sky Preservation regulations
(Zoning Regulations, Ch. 17.23). The location of exterior lighting fixtures must be clearly
indicated and building-mounted fixtures must be depicted on building elevation drawings.
All exterior lighting must be oriented, recessed, or shielded to prevent light trespass and
pollution.
4. Landscape Plan: Plans submitted for construction permits shall include a landscaping plan
indicating the extent of landscaped area, hardscape, plant selection, and method of irrigation,
consistent with Community Design Guidelines, Engineering Standards, and Water-Efficient
Landscape Standards, as applicable.
5. Equipment Noise: The project shall incorporate all recommendations of the acoustic analysis
prepared by David Dubbink Associates, and plans submitted for construction permits shall
provide details pertaining to the vehicle dryer, including information about noise levels
produced to ensure that the noise generated will be consistent with the acoustic analysis
provided by the applicant and will be within acceptable limits. The equipment used for the
car wash will operate at all times in compliance with the Noise Control regulations of the San
Luis Obispo Municipal Code (Chapter 9.12).
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Resolution No. PC ####-16 Page 3
USE-2551-2015 (363 Santa Rosa Street)
6. Hours of Operation: The car wash equipment shall not be operated before 7:00 am or after
8:00 pm. This limitation is intended to avoid excessive noise levels during nighttime hours.
7. Indemnification: The applicant shall defend, indemnify and hold harmless the City and/or its
agents, officers and employees from any claim, action or proceeding against the City and/or
its agents, officers or employees to attack, set aside, void or annul, the approval by the City
of this project, and all actions relating thereto, including but not limited to environmental
review (“Indemnified Claims”). The City shall promptly notify the applicant of any
Indemnified Claim upon being presented with the Indemnified Claim and City shall fully
cooperate in the defense against an Indemnified Claim."
Public Works
8. If this project is considered to be part of a larger “Common Plan of Development” with 1042
Olive Street, then the development plans shall include compliance with a Stormwater
Pollution Prevention Plan for land disturbance of one or more acres and the Post
Construction Stormwater Requirements promulgated by the Regional Water Quality Control
Board for the redeveloped sites.
On motion by Commissioner ______, seconded by Commissioner _____, and on the
following roll call vote:
AYES:
NOES:
REFRAIN:
ABSENT:
The foregoing resolution was passed and adopted this 11th day of May, 2016.
_____________________________
Xzandrea Fowler, Secretary
Planning Commission
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VICINITY MAP File No. USE-2551-2015363 Santa Rosa St.¯
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David Dubbink Associates
Acoustic Analysis
For the
Splash N’Dash Carwash
363 Santa Rosa Street
San Luis Obispo, CA
Prepared by:
David Dubbink Associates
864 Osos Street, Ste D
San Luis Obispo, CA 93401
February 17, 2016
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David Dubbink Associates
Table of Contents
The Acoustic Setting……………………………………………………..1
Assessing the Noise Environment……………………………….1
Other Sound Levels Estimates……………………………………2
Applying the City’s Municipal Code and Noise Ordinance……...3
Noise from Carwash Equipment………………………………….4
Noise produced by Carwash Patrons……………………………..5
Sound Levels at the Apartment Complex………………………..5
Sound Levels at the Office on Montalban Street…………………6
Noise at the On-Site Manger’s Unit………………………………6
Design Mitigations………………………………………………..6
Construction Noise………………………………………………..7
Recommendations…………………………………………………7
CEQA Determinations…………………………………………….7
Appendix A: Hourly Leq Contributions to CNEL/DNL………………….9
Appendix B: Questions from the CEQA Checklist………………………..10
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Figure 1: Area View with Site Plan
Acoustic Study
Splash N’Dash Carwash
This report is an analysis of
acoustic issues for a proposed car
wash to be located at the
intersections of Santa Rosa and
Montalban Streets, in the city of
San Luis Obispo.Figure 1 shows
the site plan and the vici nity.
This study concludes that the
project is consistent with City
policy.This assumes mitigations
are incorporated into the design as
propose by the builder and as
recommended in this report.
The Acoustic Setting
Traffic is the major noise source at
this location.The site fronts onto
Santa Rosa Street which is also
Highway 1. Olive Street is an entry
to Southbound Highway 101.
Previously there was a gas station
at this site. This has been cleared
and the surface is a mix of earth
and gravel with scattered weed
growth.
Assessing the Noise Environment
Noise levels at the site were monitored on February 8, 2016 at a location represented by
the red dot on Figure 11.The distance from this location to the centerline of Santa Rosa is
95 feet.The monitoring period began at 4:00 p.m.There was no wind and the
temperature was in the 70s.Traffic was heavy and generally traveling at the posted speed
limit of 35 mph. There was occasional slowing of the curb lane when there was a backup
of vehicles making the right turn onto Olive Street .
Table 1 shows the level readings at the location as measured by three different metrics.
The Min is the quietest moment and the Max, the loudest. The Leq metric represents the
1 A Brüel & Kjær Precision Integrating Sound Level Meter, Type 2230 was used in making the
measurements. The meter was calibrated before and after the survey usin g a B&K Acoustic Calibrator
Model 4231. The readings were determined to be accurate .The sound level meter was at a 5 foot level.
Figure 1: Parcel Location
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Table 1: Sound Level Measurements
average sound energy over a ten minute measurement period.(This metric is commonly
used in assessing community noise exposure ).There were two ten minute measuring
sessions. The levels measured in the two sessions are essentially the same suggesting that
the noise levels are a representative of the 4 p.m . to 5 p.m. time period. .
Other Sound Level Estimates
There are several methodologies for evaluating noise levels apart from direct noise
measurement over a limited time period. The Federal Highway Administration (FHWA)
has developed a Traffic Noise Model (TNM). This noise estimation tool is the national
standard for roadway noise evaluation. Also, noise level contours have been computed
and published as maps in the City’s Noise Element.
The Federal highway noise forecasting system, the TNM, incorporates multiple
components; the traffic volume, the mix of cars, medium and heavy trucks, the speed, the
distance, and a representation of topographic conditions.Caltrans publishes regular
updates on traffic counts for state highways along with reports on the percentages of cars
and trucks.The City provided hourly count data for two weekdays, March 4th and 5th in
2014.The data on traffic flows on Santa Rosa, coupled with the FHWA model,can
produce estimates of noise exposure to corroborate the on -site monitoring.In our
computation, average traffic speed is estimated to be 35 mph. The traffic mix is 93%
autos,4.5% medium trucks and 2.5% heavy trucks.Surface conditions were assumed to
be a mix of hard and soft site conditions.The noise measuring position was set to 95 feet
distant from the Santa Rosa Street centerline. There was no consideration of topography
as the site is level with the street.
The resulting computations of hourly and daily sound levels using the TNM are
illustrated in Appendix A. During the hour beginning at 4 p.m., which corresponds to the
monitoring period, the hourly level is estimated to be an Leq of 67.6 under hard site
conditions and 63.7 Leq with soft site conditions2.The soft/hard site average is 65.6 Ldn
The Noise Element of the City’s General Plan describes noise exposure in terms of the
Ldn metric. This metric is a “cousin” to Leq in that it represents noi se energy over a
period of time. However, in the case of Ldn, the measurement period is a 24 hour day,
and there is a 10 decibel penalt y added to nighttime sounds (10 p.m. to 7 am.).Looking at
the Ldn for the 24 hours of activity detailed in Appendix A the average of the hard and
soft site estimates is 65.2 Ldn. There is a rule of thumb among roadway noise analysts
that the Leq for the peak hour of travel will approximate the Ldn value. In this case,
Appendix A indicates the Ldn value is 65.9 for the peak hour which occurs between 5
and 6 PM.This is essentially the same as the Ldn of 65.2 computed over an entire day.
2 A soft site would be absorbent, like grass. A hard site would be reflective, like water.
Minimum Maximum Leq
Session 1 54.0 69.8 63.2
Session 2 53.1 70.1 62.7
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The Technical Reference document that describes the analysis made for the City’s Noise
Element reports the distance to the 60 ,65 and 70 Ldn contours for the road segment from
Highway 101 to Highland Drive. The distance to the 60 Ldn contour under future
conditions is estimated to be 385 feet.The distance to the 65 Ldn contour is 178 feet and
the distance to the 70 Ldn contour is 83 feet 3. Applying some reverse engineering, the
Noise Element representation of sound the sound level at the on site monitoring distance
would be 69.1 Ldn.
Table 2 compares the site measurement with the computed metrics.The measured sound
level is less than the calculated levels.The measured level made during the 4 p.m to 5
p.m. period was 63.2.For the TNM, the value shown is for the corresponding time period
where the computed level, assuming an even mix of soft and hard surfaces, is 6 5.6.
Interpolating the level at the measuring point from the City’s Noise Element gives an Ldn
value of 69.1.
There are several possible explanations for the divergence. Neither the TNM estimation
nor the Noise Element mapping includes a consideration of topography or screening by
other structures.During the measurement periods, it was observed that traffic regularly
slowed with each buildup of vehicles turning right onto Olive Street. The turning lane is
not sufficient to handle all of the turn traffic. Had a slower speed been assumed in the
computation, the Ldn estimate would have been less. This also could explain the
divergence from the values used in the noise element. The Technical Reference Manual
includes the computation assumptions and indicates the speed on Santa Rosa was set at
45 mph for the forecast in the Noise Element .Lowering this to 35 mph would trim 3
decibels from the estimate.For the purposes of this study it will be assumed that sound
levels at the site are in a range between 64 and 66 Ldn. This is more than the measured
level,and matches the TNM levels and the value extrapolated from the Noise Element
(with a 3 decibel adjustment to reflect the drop from 45 to 35 mph).
Applying the City’s Municipal Code and Noise Ordinance
The attention given to determining the current noise level at the site reflects its
importance in defining the proper noise limit.Section 9.12.060 of the San Luis Obispo
Municipal Code gives a table of noise levels that are not to be exceeded for various
zoning categories over specified time periods (Table No. 1, page 9).The Code contains a
provision that, in cases where the ambient level differs from the permissible level,as it
does here, the allowable noise exposure standard “shall be adjusted in 5 dB increments . .
.to reflect the ambient noise level”4.The text indicates that the standards are to applied at
3 Technical Reference Document for the Noise Element, page 3-11.
4 SLO Municipal Code, 9-12 060.
Measurement (Sample 1,Leq 4-5 p.m.)63.2
TNM Estimate (Leq –4 to 5 PM)65.6
Noise Element Map (Ldn)69.1
Table 2: Comparisons of Estimates
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the property line of receiving land uses . The bordering apartment structures to the west is
the closest noise sensitive use. Offices are identified as noise sensitive activities and there
is a law office on the opposite side of Montalban Street . However,the land use
designation is tourist commercial and the Code is w ritten in terms of land use categories.
For mult-family residential land uses the permissible exposure level is 55 decibels
daytime and 50 night. For offices, the maximum is daytime limit is 60 and the n ighttime
limit is 55. The 63.2 Leq measured on-site was using the Leq metric and this can be used
to interpolate the levels at the property line of the apartment structure and at the office .
The distance form the centerline of Santa Rosa to the apartment property line is 185 feet.
This translates to a decibel level of 595. This is more than the permitted level of 55
decibels so the standard for daytime noise exposure shifts to a maximum of 60 decibels.
The office building borders the Santa Rosa Street right of way. At the property line the
decibel level would be 72.4. Applying the 5 decibel shift, the permitted noise limit is 75
decibels
Noise from Carwash Equipment
The carwash layout is shown in Figure 1. Cars enter the facility from Montalban Street
and drive forward toward the far property line where the payment station is located.
Following the transaction they turn left, moving in a counter-clockwise direction toward
Santa Rosa, making another left turn into the carwash tunnel. The exit tunnel faces
Montalban and another left turn. The driver can ex it the property next to the entry
driveway or stop at the area with vacuum units.
A car wash operation includes multiple noise sources. Of these, the most significant is the
drying blower at the exit of the wash tunnel. The vacuum units provided for cust omers
are an additional noise source.In the following paragraphs both of these sound sources
are considered, starting with The vacuum units.
Noise from the vacuum units will not be a difficulty for this project. The individual
vacuum stations connect to a centralized unit that provides the needed suction for a dozen
stations.The vacuum fan is to be located within a concrete block enclosure next to the
carwash tunnel. The shielding will lessen fan noise to the point where it will not be
noticeable at the already noisy site.Manufacturer’s specifications indicate a sound ouput
level of 55 dB and full operation measured at 50 feet from the source.The present
ambient sound at the monitoring point is in the realm of 65 decibels.
Figure 2 illustrates the directionality of sound from the drying units at the end of a
carwash tunnel. The darker gray rectangle at the center of the diagram represents the
tunnel exit. The concentric circles represent sound levels at 20 decibel intervals. The
lighter gray circle shows the 70 decibel level. The irregular outlines show the measured
pattern of sound radiation at times the blowers are in operation6. All sound levels are
measured 50 feet from the source. Two different types of blowers have been evaluated.
5 Applying a 6 dB reduction with each doubling of distance.6 The data for this diagram is based on measurements made by DDA. Measurements were made at 45
degree steps, fifty feet from the end of the wash tunnel.
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David Dubbink Associates Page 5 of 10
Figure 2: Sound Directionality
The red line shows the pattern from the quieter
blower and the blue line shows operation of
blowers that are slightly louder.
The sound from the louder blowers was measured
at 78 decibels directly in alignment with the outlet.
At a 90 degree angle from the centerline of the
wash tunnel the level is reduced to 67 decibels. The
90 degree angle represents the orientation of the
closest residential units in the apartment structure
to the west. The difference, due to directionality, is
a 11 decibel reduction.
Noise produced by Carwash Patrons
At times, customers of the carwash facility or their vehicles will produce noise at levels
that could be bothersome to neighbors. But such problems apply to any public space and
are difficult to manage. The neighboring properties ar e already impacted by varying noise
levels with activities along Santa Rosa Street. Carwash operations and activities at the
vacuum stations will add to the present day sound levels but, at least in the mathematics
of decibel addition and time averaged metrics, the increment of added sound does not
produce a significant change.
Sound Levels at the Apartment Complex
In estimating the sound level that would be experienced at the closest apartment structure,
three further adjustments are required;
1.Adjustment for distance,
2.Adjustment for the wing wall at the exit
3.Adjustment to reflect the hourly averaging of activities..
Sound, traveling over a paved surface, attenuates at around six decibels with each
doubling of distance. The residential property line is about 120 feet from the tunnel exit.
At this distance and at this angle, sound from the noisier dryer blower would be
attenuated to 59 decibels.The extension of a wing wall at the wash tunnel exit would
further reduce sound levels in the direction of t he apartment units. It is estimated that the
wall extension would lessen noise levels by 5 decibels, dropping exposure to 54 decibels.
The Leq metric represents the acoustical average of sound energy over time. The blowers
operate only when a vehicle is present. Based on observations at a carwash with
equipment resembling the Splash N’Dash setup , it is estimated that, during a busy hour,
the blowers would be in operation only half the clock time . The hourly averaging of the
blowers in operation or not in operation would reduce the averaged sound of the blowers
by 3 decibels over an hour with a resulting Leq level at the west property line of 51
decibels. Sound at this level is well within the City’s standard of 60 decibels .
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David Dubbink Associates Page 6 of 10
Sound Levels at the Office on Montalban Street
The situation is similar for the office structure on the opposite side of Montalban. In this
case, the sound from the blower source is 78 decibels in direct alignment with the wash
tunnel as measured at 50 feet. Making the adjustment for t he 100 foot distance to the
office property line, the level drops to 72 decibels. Adjusting for part time operation
brings the Leq down to 69. This is less than the permitted 75 Leq maximum.
Noise at the On-Site Manager’s Unit
Noise levels will be high at the manager’s unit above the pay kiosk The sound exposure
is similar to that of the neighboring apartments and interior noise levels will conform to
City standards. One purpose of having a manager’s unit on site is to maintain vigilance
over the carwash and its equipment. It is not appropriate to totally isolate the manager’s
unit from the acoustic environment.
Design Mitigations
The design for the project incorporates multiple and effective sound reduction features.
The wash tunnel is sited at the front of the property, as far as possible from the
neighboring apartments.There are multiple wing wall to deflect sound. There is a 12
foot, solid barrier wall borders the carwash exit which further reduces noise in the
Figure 3: Design Mitigations
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David Dubbink Associates Page 7 of 10
direction of the apartments.There is also a sound wall positioned between the payment
kiosk and the apartments. Another shelters the trash area. The fan for the vacuum stations
is in a concrete enclosure nest to the equipment tunnel .
Construction Noise
The City’s Municipal Code provides special standards for noise from construction
activities7. The concern is sounds that create a noise disturbance across a residential
property line.
Noise outside of the hours of 7 AM to 7 PM, or any time on Sunday or Holidays is
prohibited. Maximum sound permitted for station equipment is 75 dBA. For mobile
equipment the limit is 85 dBA. The Code also specifies that machinery be equipped with
input or exhaust silencers in proper working order.
Adherence to these standards construction should be made a condition of approval. It
should be further recommended that stationary, noise producing construction equipment
such as compressors, should be located as far away from the existing residences as
feasible.
Recommendations
1.The multiple noise mitigation features of the design should be incorporated into
the final product.
2.The central fan for the vacuum units should be in a concrete enclosure.
3.There should be signage in the vacuum area that asks patrons to limit noise for the
benefit of nearby residents.
4.Construction activities should be limited to the hours specified in the Municipal
Code as described above. The equipment recommendations should be included.
5.Stationary construction equipment producing noise should be located as far from
the apartment structures as feasible.
CEQA Determinations
The CEQA Guidelines include several questions related to the noise impact of projects.
These are replicated in Appendix B.In all cases the impacts will be less than significant .
1) The project, with recommended design features and mitigations,will not result
in significant exposure of persons to or generation of noise levels in excess of
standards established in the Noise Element of the City’s general plan, or the
Municipal Code. Exposure levels are also consistent with or below limits
suggested by state and federal agencies.
2) A second CEQA concern involves ground born vibrations. Apart from the
possibility of periods of ground vibration during construction , activities at the
7 SLO Municipal Code, Section 9.12.050
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David Dubbink Associates Page 8 of 10
parcel locations will not produce vibrations that would be felt beyond the property
line.
3)The project will not create a substantial permanent increase in ambient noise
levels in the project vicinity above levels existing without the project.
4) During the construction phase of the project, there will be a temporary increase
in ambient noise levels in the project vicinity above levels existing without the
project. However the city allows construction activities that temporarily exceed
standards if the work conforms to guidelines for construction activities. Project
conditions should reflect the city’s policies regarding the timing and nature of
construction work.
5) The other questions in the Guidelines have to do with airport proximity. The
project is located well beyond the outermo st noise contour limits for the San Luis
Obispo and Oceana airports.
With the recommended conditions the Splash N’Dash Carwash will conform to the City’s
noise regulations.
Contact me should there be any questions or need to address additional issues.
Sincerely,
David T. Dubbink, Ph.D, AICP
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David Dubbink Associates Page 9 of 10
Appendix A
Hourly Contributions to
CNEL/DNL
Day
SLO
Hourly
Count Cars
Medium
Trucks
Heavy
Trucks Total
LEQ
Hard
LEQ
Soft
7 0.0219 692 34 18 744 62.1 58.2
8 0.0555 1750 86 46 1882 66.1 62.2
9 0.0713 2251 110 59 2420 67.2 63.3
10 0.0597 1884 92 50 2026 66.4 62.6
11 0.0565 1782 87 47 1916 66.2 62.3
12 0.0666 2102 103 55 2260 66.9 63.0
1 0.0735 2320 114 61 2495 67.3 63.5
2 0.0723 2282 112 60 2454 67.3 63.4
3 0.0712 2248 110 59 2417 67.2 63.3
4 0.0774 2443 120 64 2627 67.6 63.7
5 0.0827 2611 128 69 2807 67.9 64.0
6 0.0812 2561 125 67 2754 67.8 63.9
Evening
7 0.0591 1865 91 49 2005 66.4 62.5
8 0.0422 1333 65 35 1433 64.9 61.1
9 0.0337 1063 52 28 1143 63.9 60.1
Night
10 0.0267 842 41 22 905 62.9 59.1
11 0.0154 486 24 13 523 60.6 56.7
12 0.0083 263 13 7 283 57.9 54.0
1 0.0052 164 8 4 176 55.8 51.9
2 0.0029 93 5 2 100 53.3 49.3
3 0.0022 71 3 2 76 52.1 48.3
4 0.0014 46 2 1 49 50.0 46.1
5 0.0027 84 4 2 90 52.8 48.9
6 0.0104 327 16 9 352 58.9 55.0
1.0000 31561 1544 831 33937
CNEL Ldn
Car Medium
Truck
Heavy
Truck Total (ADT)Hard
Site 67.8 67.1
31,561 1,544 831 33,937
Soft
Site 63.9 63.2
0.93 0.055 12,829
1/2 Soft
1/2
Hard
65.9 65.2
0.93 0.0455 0.0245 1.0000
The table was constructed as follows:
Speed is assumed to be 35 mph. Distance to the highway centerline is 95 feet.
The total ADT figure and hourly breakdown are based on SLO City data.
The breakdown of the vehicle mix is from the Caltrans report on truck percentages.
The hourly LEQs for each hour were calculated at the monitoring distance using
TNMLook.
The resulting hourly Leqs were evaluated to calculate Ldn and CNEL values.
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Appendix B
Questions from the CEQA Checklist
XII. NOISE:Would the project result in:
a)Exposure of persons to or generation of noise levels in excess of standards established in the
local general plan or noise ordinance, or applicable standards of other agencies?
b)Exposure of persons to or generation of excessive groundborne vibration or groundborne noise
levels?
c)A substantial permanent increase in ambient noise levels in the project vicinity above levels
existing without the project?
d)A substantial temporary or periodic increase in ambient noise levels in the project vicinity above
levels existing without the project?
e)For a project located within 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?
f)For a project within the vicinity of a private airstrip,would the project expose people residing or
working in the project area to excessive noise levels?
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