HomeMy WebLinkAboutCT 15-06; THE WAVE; NOISE IMPACT STUDY; 2015-07-20City of Carlsbad
The Wave Mixed Use
Dev~Jopment Project
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Noise Impact Study
July 2015
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NOISE IMPACT STUDY
THE WA VE MIXED USE DEVELOPMENT PROJECT
Prepared by:
City of Carlsbad
1635 Faraday A venue
Carlsbad, CA 92008
(760) 602-4600
Prepared with the assistance of:
Rincon Consultants, Inc.
5135 A venida Encinas, Suite A
Carlsbad, California 92008
(760) 918-9444
July 2015
This report prepared on 50% recycled paper with 50% post-consumer content.
The Wave Mixed Use Development Project
Noise Impact Study
Table of Contents
Page
Introduction ............................................................................................................................................. 1
Project Description .................................................................................................................................. 1
Setting ................................................................................................................................................... 1
Overview of Sound Measurement ................................................................................................. 1
Sensitive Receptors .......................................................................................................................... 3
Project Site Setting ............................................................................................................................ 3
Regulatory Setting ............................................................................................................................ 6
Vibration Standards ......................................................................................................................... 6
Impact Analysis ....................................................................................................................................... 7
Methodology and Significance Thresholds .................................................................................. 7
Temporary Construction Noise ...................................................................................................... 8
Construction Noise Reduction Measures ..................................................................................... 9
Temporary Construction-Related Vibration .............................................................................. 10
Long-Term Operational Noise Exposure .................................................................................... 11
References .............................................................................................................................................. 14
List of Figures
Figure 1-Project Location .................................................................................................................... 2
Figure 2 -Noise Monitoring Locations ............................................................................................... 6
List of Tables
Table 1 Noise Monitoring Results ........................................................................................................ 6
Table 2 Typical Construction Equipment Noise Levels .................................................................... 8
Table 3 Typical Maximum Construction Noise Levels at Various Distances from Project
Construction ............................................................................................................................. 9
Table 4 Vibration Source Levels for Construction Equipment ....................................................... 10
Table 5 Existing and Project Related Noise Levels .......................................................................... 11
Appendices
Appendix A Transportation Noise Model Files
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INTRODUCTION
This report is an analysis of the potential noise impacts associated with The Wave, a mixed use
development proposed for construction in the City of Carlsbad. The report has been prepared
by Rincon Consultants, Inc. under contract to the applicant to support the environmental
review process and address deficiencies in the application referenced in the June 15, 2015,
Notice of Incomplete letter received from the City of Carlsbad. This study analyzes the potential
for temporary impacts associated with construction activity and long-term impacts associated
with operation of the proposed project.
PROJECT DESCRIPTION
The Wave is a residential/ commercial mixed use project proposed for development in
Carlsbad, CA, on Assessor Parcel Number 203-101-20 (Figure 1). The project entails construction
of a new 4-story mixed use commercial and multi-family building located on a 10,878 square
foot lot at 2646 State Street (north of Beech Street and east of Carlsbad Village Station station) in
downtown Carlsbad. The building would contain 21 residential and timeshare units (12
timeshare units, 1 apartment and 8 condominiums) in floors 2-4. The ground floor would
contain 1,165 square feet of commercial, lobby and office space. A total of 36 parking spaces
would be provided on-site at ground level (16 spaces) and in an underground parking garage
(20 spaces). The project would require the demolition of an existing residential structure prior to
construction. Decisions to approve entitlements associated with the proposed project are
discretionary; thus, compliance with the California Environmental Quality Act (CEQA) will be
required. This noise impact study will be used by the City of Carlsbad to support the
discretionary review process.
SETTING
Overview of Sound Measurement
Noise level (or volume) is generally measured in decibels (dB) using the A-weighted sound
pressure level (dBA). The A-weighting scale is an adjustment to the actual sound pressure levels
to be consistent with that of human hearing response, which is most sensitive to frequencies
around 4,000 Hertz (about the highest note on a piano) and less sensitive to low frequencies
(below 100 Hertz).
Sound pressure level is measured on a logarithmic scale with the O dB level based on the lowest
detectable sound pressure level that people can perceive (an audible sound that is not zero
sound pressure level). Based on the logarithmic scale, a doubling of sound energy is equivalent
to an increase of 3 dBA, and a sound that is 10 dBA less than the ambient sound level has no
effect on ambient noise. Because of the nature of the human ear, a sound must be about 10 dBA
greater than the reference sound to be judged as twice as loud. In general, a 3 dBA change in
community noise levels is noticeable, while 1-2 dB changes generally are not perceived. Quiet
suburban areas typically have noise levels in the range of 40-50 dBA, while arterial streets are in
the 50-60+ dBA range. Normal conversational levels are in the 60-65 dBA range, and ambient
noise levels greater than 65 dBA can interrupt conversations. Noise levels typically attenuate (or
drop off) at a rate of 6 dBA per doubling of distance from point sources (i.e., industrial
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The Wave Mixed Use Development Project
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The Wave Mixed Use Development Project
Noise Impact Study
machinery). Noise from lightly traveled roads typically attenuates at a rate of about 4.5 dBA per
doubling of distance. Noise from heavily traveled roads typically attenuates at about 3 dBA per
doubling of distance. Noise levels may also be reduced by intervening structures; generally, a
single row of buildings between the receptor and the noise source reduces the noise level by
about 5 dBA, while a solid wall or berm reduces noise levels by 5 to 10 dBA. The manner in
which older homes in California were constructed (approximately 30 years old or older)
generally provides a reduction of exterior-to-interior noise levels of about 20 to 25 dBA with
closed windows. The exterior-to-interior reduction of newer residential units and office
buildings is generally 30 dBA or more (HMMH, 2006).
In addition to the instantaneous measurement of sound levels, the duration of sound is
important since sounds that occur over a long period of time are more likely to be an annoyance
or cause direct physical damage or environmental stress. One of the most frequently used noise
metrics that considers both duration and sound power level is the equivalent noise level (Leq).
The Leq is defined as the single steady A-weighted level that is equivalent to the same amount
of energy as that contained in the actual fluctuating levels over a period of time (essentially, the
average noise level). Typically, Leq is summed over a one-hour period. Lmax is the highest
RMS (root mean squared) sound pressure level within the measuring period, and Lmin is the
lowest RMS sound pressure level within the measuring period.
The time period in which noise occurs is also important since noise that occurs at night tends to
be more disturbing than that which occurs during the day. Community noise is usually
measured using the Day~Night Average Level (Ldn), which is the 24-hour average noise level
with a 10-dBA penalty for noise occurring during nighttime (10 p.m. to 7 a.m.) hours, or the
Community Noise Equivalent Level (CNEL), which is the 24-hour average noise level with a 5
dBA penalty for noise occurring from 7 p.m. to 10 p.m. and a 10 dBA penalty for noise
occurring from 10 p.m. to 7 a.m. Noise levels described by Ldn and CNEL usually do not differ
by more than 1 dBA.
Sensitive Receptors
Noise exposure goals for various types of land uses reflect the varying noise sensitivities
associated with each of these uses. The City of Carlsbad General Plan Noise Element includes a
variety of land use and development types that are noise sensitive including residences,
schools, churches, hospitals and convalescent care facilities. Nearby sensitive receptors are
single-family residences adjacent to the east and a mobile home park (Carlsbad Trailer Pla~to
the north. Commercial are located to the west and south.
Project Site Setting
The most common and primary sources of noise in the project site vicinity are motor vehicles
(e.g., automobiles, buses, trucks, and motorcycles) along State Street. Motor vehicle noise is of
concern because it is characterized by a high number of individual events, which often create a
sustained noise level, and because of its proximity to noise sensitive uses. Interstate 5 is located
over 2,000 feet to the east. It is not audible as background noise and does not contribute to
overall noise levels at the project site. Traffic on State Street is the primary noise source in the
area; however, commercial uses (i.e., car wash and tire store) contribute to ambient noise levels.
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The Wave Mixed Use Development Project
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The Atchison, Topeka and Santa Fe Railroad (AT&SF) rail corridor is located two blocks
(approximately 350 feet) to the west. This segment of the Los Angeles -San Diego -San Luis
Obispo (LOSSAN) corridor is the second busiest passenger and freight rail corridor in the
United States. According to the rail timetables, up to 50 trains (40 passenger and 10 freight
trains) use the corridor segment daily between Oceanside and the Santa Fe Depot in downtown
San Diego. Existing rail operations are audible at the project site, particularly the warning
horns/bells that are used when trains are approaching the Carlsbad Village Drive crossing and
station. Train operations affect ambient noise conditions within the area. McClellan-Palomar
Airport is located approximately 4.5 miles southeast of the site. The site is outside the airport
influence area; however, aircraft operations are audible as a distant source and contribute
negligibly to existing noise levels. No other noise sources are near the project site.
The City of Carlsbad General Plan Noise Element (1995) is currently being updated so the
existing General Plan Noise Element is used for reference. The Noise Element provides noise
contours associated with transportation corridors (i.e., roadways, railroad and airport). This
provides a graphic illustration of sound levels near road corridors, but typically does not
include effects of landforms and adjacent structures. Generally, barriers between a source and
receiver absorb or reflect noise resulting in a quieter environment. Where barriers or landforms
do not interrupt the noise transmission path from source to receiver, the contours prove to be
reasonable estimates of the average noise level from roadway traffic. In areas where barriers or
landforms interrupt sound transmission, the noise contours overestimate the extent to which a
source intrudes into neighboring areas. The noise contour distances describe worst-case
conditions because they do not account for any obstructions to the noise path, such as walls,
berms, or buildings. As noted above, railroad noise is audible when train pass-by events occur.
The contours provided in the General Plan Noise Element provide a reasonable prediction of
rail noise levels at the site. Noise contours show the eastern project boundary is east of the 65
dBA/CNEL contour interval defined for the railroad track.
To gather data on the general noise environment at the project site, two weekday morning 15-
minute noise measurements were acquired in proximity to the project site on July 16, 2015,
using an ANSI Type II integrating sound level meter. Site 1 is located in the southwest comer of
the self-service car wash parking lot; Site 2 is located in the Community Interface Services
parking lot. Both locations approximate existing noise conditions at the project site. The
predominant noise source in the area during monitoring at Site 1 was traffic on State Street.
However, construction activity occurring on the west side of State Street was audible as was
sound from the adjacent self-service car wash facility located north of the site and tire store
located to the west. The predominant noise source at Site 2 was parking lot operations and
activities occurring at the adjacent mobile home park. Distant traffic on State Street to the west
and Roosevelt Street to the east was audible but not the primary noise source. The temperature
during monitoring was 70 degrees Fahrenheit with no measurable wind.
During monitoring, a total of 50 cars/light trucks and two medium (six tires/two axles) passed
the monitoring location. A total of 16 cars/light trucks and one medium delivery truck passed
the monitoring location along State Street west of the site. One North County Transit District
Coaster heavy rail stop occurred at Carlsbad Village Station during the first monitoring episode.
An Amtrak pass by event occurred during the second monitoring episode. Table 1 identifies the
noise measurement locations and measured noise levels. Monitoring locations are shown in
Figure 2. The highest Leq was 59.6 dBA during the morning monitoring period.
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II I! Project Location
• Monitoring Site 1
Monitoring Site 2
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Noise Monitoring Locations Figure 2
City of Carlsbad
The Wave Mixed Use Development Project
Noise Impact Study
Table 1
Noise Monitoring Results
Measurement Location Primary Noise
Source
Southwest comer of the Carlsbad Self Service Car
Wash parking lot approximately 50 feet east of State T raffle/Construction
Street centerline.
West side of Community Interface Services parking Commercial and
lot between State Street to the west and Roosevelt mobile home park
Street to the east. activity
Source: Field visit using ANSI Type I/ Integrating sound level meter.
Regulatory Setting
Sample Time Leq (dBA)
Weekday morning 57.9
Weekday morning 59.6
In 1976, the California Department of Health, State Office of Noise Control published a
recommended noise/land use compatibility matrix which many jurisdictions have adopted as a
standard in their general plan noise elements. This matrix indicates that residential land uses
and other noise sensitive receptors preferentially should be located in areas where outdoor
ambient noise levels do not exceed 65 to 70 dBA (CNEL or Ldn).
Municipal Code and Noise Guideline Manual. The City of_ Carlsbad has established
noise guidelines in the Noise Element of the City1s General Plan (City of Carlsbad, 1995) that are
applicable for transportation noise sources. The noise guidelines identify compatible exterior
noise levels for various land use types. Residential land uses are considered normally
acceptable up to 60 dB CNEL. Commercial land uses are considered normally acceptable up to
65 dBA CNEL and conditionally acceptable up to 75 dBA.
The City of Carlsbad Municipal Code regulates construction noise by limiting the hours of
operation (City of Carlsbad 2003). Construction activities are allowed to occur Monday through
Friday between the hours of 7 a.m. to sunset; and on Saturdays from 8 a.m. to sunset, excluding
legal holidays. The City does not have quantitative noise level limits (i.e., based on sound
levels) for general nuisance noise such as that associated with stationary equipment located on
private property.
For the purpose of this study, the residential standard of 60 dBA CNEL is used to evaluate
potential exterior noise impacts associated with the proposed project. An interior noise standard
of 45 dBA CNEL is used herein as referenced in the City of Carlsbad Noise Guidelines Manual
(1995).
Vibration Standards
Vibration is a unique form of noise as the energy is transmitted through buildings, structures
and the ground whereas audible noise energy is transmitted through the air. Thus, vibration is
generally felt rather than heard. The ground motion caused by vibration is measured as particle
velocity in inches per second and is referenced as vibration decibels (V dB). The vibration
velocity level threshold of perception for humans is approximately 65 V dB. A vibration velocity
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of 75 V dB is the approximate dividing line between barely perceptible and distinctly perceptible
levels.
City policies do not address construction-related vibration; thus, for the purpose of evaluating
project-related vibration impacts, thresholds established in the Federal Transit Administration's
(FTA) Transit Noise and Vibration Impact Assessment (May 2006) are used. A threshold of 65 VdB
is used for buildings where low ambient vibration is essential for interior operations. These
buildings include hospitals and recording studios. A threshold of 72 V dB is used for residences
and buildings where people normally sleep (i.e., hotels and rest homes). A threshold of 75 VdB
is used for institutional land uses where activities occur primarily during the daytime (i.e.,
churches and schools). The threshold used for the proposed project is 72 VdB as residences are
the only sensitive receptors near the site.
Construction activities such as blasting, pile driving, demolition, excavation or drilling have the
potential to generate ground vibrations near structures. With respect to ground-borne vibration
impacts on structures, the FTA states that ground-borne vibration levels in excess of 100 VdB
would damage fragile buildings and levels in excess of 95 V dB would damage extremely fragile
historic buildings. No historic buildings are known to occur near the site; thus, 100 V dB is used
to quantify potential vibration impacts to neighboring structures. Construction activities
referenced above that would generate significant vibration levels are not proposed. However, to
provide information for use in completing the CEQA evaluation, construction-related vibration
impacts are evaluated using the above referenced criteria.
IMP ACT ANALYSIS
Methodology and Significance Thresholds
· Construction noise estimates are based upon noise levels reported by the Federal Transit
Administration, Office of Planning and Environment, and the distance to nearby sensitive
receptors. Reference noise levels from that document were used to estimate noise levels at
nearby sensitive receptors based on a standard noise attenuation rate of 6 dB per doubling of
distance (line-of-sight method of sound attenuation).
Noise levels associated with existing and future traffic along area roadways were calculated
using the Traffic Noise Model Version 2.5 Look-Up Tables (U.S. Department of Transportation,
Federal Highway Administration [FHW A], April 2004) (noise modeling data sheets are
provided in Appendix A).
This study also estimates potential noise levels at the project site related to operation of the
AT&SF rail line, which is located approximately 350 feet west of the site. A proprietary software
program developed by Rincon Consultants, Inc. was used to perform noise calculations for rail
operations. Specific assumptions used in the analysis are described below.
A noise increase greater than 3 dBA is readily perceptible to the average human ear; and thus, is
the level considered a substantial noise increase related to traffic operations. However, within
the City of Carlsbad, noise impacts are also considered significant if noise levels would exceed
60 dBA CNEL. For the purpose of this evaluation, the peak hour Leq is used for traffic noise as
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The Wave Mixed Use Development Project
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it provides a more conservative estimate of potential noise levels. The CNEL is used within the
rail noise discussion.
All mechanical equipment associated with the project would be located in enclosed rooms on
the roof top. Mechanical noise is not expected to be audible at adjacent receivers.
Temporary Construction Noise
The main sources of noise during construction activities would include heavy machinery used
during demolition, grading, and clearing the site, as well as equipment used during building
construction and paving. Table 2 demonstrates the typical noise levels associated with heavy
construction equipment. As shown, average noise levels associated with the use of heavy
equipment at construction sites can range from about 81 to 95 dBA at 25 feet from the source,
depending upon the types of equipment in operation at any given time and phase of
construction (Hanson, Towers, and Meister, May 2006).
Table 2
Typical Construction Equipment Noise Levels
Typical Level Typical Level {dBA) Typical Level (dBA)
Equipment Onsite (dBA) 25 Feet 50 Feet from the 100 Feet from the
from the Source Source Source
Air Compressor 84 78 64
Backhoe 84 78 64
Bobcat Tractor 84 78 64
Concrete Mixer 85 79 73
Bulldozer 88 82 76
Jack Hammer 95 89 83
Pavement Roller 86 80 74
Street Sweeper 88 82 76
Man Lift 81 75 69
Dump Truck 82 76 70
Source: Noise levels based on FHWA Roadway Construction Noise Model (2006) Users Guide Table 1.
Noise levels based on actual maximum measured noise levels at 50 feet (Lmax).
Noise levels assume a noise attenuation rate of 6 dBA per doubling of distance.
Noise-sensitive uses near the project site consist of single-family residences located adjacent to
and east of the site and a mobile home park located north of the site. Construction noise will be
audible at these properties. Table 3 shows typical maximum construction noise levels at various
distances from construction activity, based on a standard noise attenuation rate of 6 dBA per
doubling of distance. The noise level used to estimate the maximum noise level that could occur
is based on use of a bulldozer as it is likely to be the noisiest type of equipment used over a
sustained period of time adjacent to neighboring residences during demolition and site
preparation activities. Actual noise levels will fluctuate throughout the day and may
periodically exceed 84 dBA depending on the type and location of equipment used and whether
multiple pieces of equipment are operating simultaneously in the same area.
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Table 3
Typical Maximum Construction Noise Levels
at Various Distances from Project
Construction
Distance from Maximum Noise Level at
Construction Receptor
(dBA)
25 feet 88
50 feet 82
100 feet 76
250 feet 70
500 feet 64
1,000 feet 58
The sensitive receptors nearest to the proposed construction site are single-family residences
located adjacent to the site along the northern and eastern property boundaries. At this
distance, noise levels from construction could be as high as 88 dBA. However, temporary
construction noise is not restricted if it occurs between the hours specific in the noise ordinance
referenced herein. While not required, temporary construction noise can be reduced by
implementing one or more of the following measures.
Construction Noise Reduction Measures
Temporary construction noise levels could be reduced through implementation of the following
measures:
r
N-1 Construction Equipment. Use electrical power to run air compressors
and similar power tools. Equip internal combustion engines with a
muffler of a type recommended by the manufacturer and in good
repair. Operate all diesel equipment with closed engine doors and
should be equipped with factory-recommended mufflers. Shield
construction equipment that continues to generate substantial noise at
the project boundaries with temporary noise barriers, such as barriers
that meet a sound transmission class (STC) rating of 25, sound
absorptive panels, or sound blankets on individual pieces of
construction equipment. Locate stationary noise-generating
equipment, such as generators and compressors, as far as practically
possible from the nearest residential property lines.
N-2 Limit Operations Adjacent to Receivers. Lim.it the number of large
pieces of equipment (i.e., bulldozers or concrete mixers) operating
adjacent to receivers to one at any given time.
N-3 Neighbor Notification. Provide notification to residential occupants
adjacent to the project site at least 24 hours prior to initiation of
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The Wave Mixed Use Development Project
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construction activities that could result in substantial noise levels at
outdoor or indoor living areas. This notification should include the
anticipated hours and duration of construction and a description of
noise reduction measures being implemented at the project site. The
notification should include a telephone number for local residents to
call to submit complaints associated with construction noise. The
notification should be posted on State Street (west) and Roosevelt
Street (east) and should be easily viewed from adjacent public areas.
Project construction would represent a temporary source of noise at the project site. Measures
N-1 through N-3 would reduce construction noise levels. No significant residual impacts
associated with construction noise are anticipated.
Temporary Construction-Related Vibration
Activities associated with residential developments do not generate vibration. Thus, this
discussion will focus on temporary vibration caused by construction. Based on the information
presented in Table 4, vibration levels could reach approximately 87 VdB at the residences
adjacent to the site during construction assuming a bulldozer is the heaviest piece of equipment
used during demolition. The nearest residences are located approximately 25 feet from the
project site's northern and eastern boundary.
As discussed below, 100 VdB is the threshold where minor damage can occur in fragile
buildings. Vibration levels are projected to be under this threshold; thus, structural damage is
not expected to occur as a result of construction activities associated with the proposed project.
Vibration levels at residential units located east and north of the project site may exceed the
groundborne velocity threshold level of 72 V dB for residences and/ or buildings where people
sleep as discussed above. However, as long as construction occurs within the prescribed hours,
the temporary impact would be considered adverse, but less than significant, since construction
would not occur during nighttime hours when people normally sleep.
Table 4
Vibration Source Levels for Construction Equipment
Equipment
Approximate VdB
25 Feet 50 Feet 60 Feet 75 Feet 100 Feet
Large Bulldozer 87 81 79 77 75
Loaded Trucks 86 80 78 76 74
Jackhammer 79 73 71 69 67
Small Bulldozer 58 52 50 48 46
Source: Federal Railroad Administration, 1998
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Long-Term Operational Noise Exposure
Exterior Traffic Noise. Traffic is the primary noise source that would be generated by
the proposed project. The proposed project would increase traffic volumes on State Street which
may cause or contribute to an increase in traffic-related noise on and adjacent to the project site.
Noise levels from traffic on State Street were estimated using the Traffic Noise Model Version
2.5 (U.S. Department of Transportation, Federal Highway Administration [FHWA], April 2004)
(see Appendix A). Traffic noise was estimated for a weekday peak hour when the proposed
project would add the largest volume of vehicles to the adjacent streets. Existing peak hour
volumes were extrapolated based on the 15-minute traffic counts performed during noise
monitoring. The peak hour is defined as the one-hour period between 7:00 am and 9:00 am and
4:00 pm and 6:00 pm when the highest volumes occur. Future traffic volumes were based on
trip generation rates published by the Institute of Transportation Engineers (ITE) publication
Trip Generation, s11i Edition for apartments. For the purpose of this analysis, the condominiums,
apartment and timeshares were assumed to have the same trip generation rate or 0.62 evening
(PM) peak hour trips per unit. This would equate to 13 trips (21 units multiplied by 0.62). The
commercial area would generate 2.71 PM peak hour trips per 1,000 square feet or 3 trips. Thus,
the proposed project would generate approximately 13 new residential trips plus 3 commercial
trips for a total of 16 PM peak hour trips. However, the trip generation rate for the existing
single-family residential use is 10 trips per day. The proposed project would replace this use;
therefore, the total increase in trips associated with the project would be 6 during the peak hour.
The trips were added to the baseline peak hour traffic on State Street to conservatively estimate
noise levels associated with the project. The posted speed limit on State Street is 25 miles per
hour (mph); however, 35 mph was the observed speed and the speed used in TNM. No stop
controls are located in proximity to the site.
Table 5 shows the existing and anticipated future (cumulative) noise levels at 30 feet from the
State Street centerline. Existing mod~led roadway noise levels are 57.9 dBA adjacent to State
Street which is the level measured in the field. To create a potentially significant and adverse
impact, project-related traffic noise levels would have to cause a 3 dBA increase or cause noise
levels to exceed 60 dBA.
Table 5
Existing and Project Related Noise Levels
Roadway Existing Existing Plus Project
Project Change
State Street adjacent to the project 57.9 dBA 58 +0.1 dBA site.
Estimates of noise generated by traffic from roadway centerline at 30 feet for State Street.
Refer to Appendix for full noise model output.
Source: Federal Highway Administration Traffic Noise Model Version 2.5 Look-Up Tables.
Significant
Impact
No
As shown in Table 5, the expected exterior noise level increase associated with project traffic on
State Street would be 0.1 dBA. As discussed, the net increase in trips associated with the
proposed project would add 6 peak hour trips. The associated increase in noise levels would not
be greater than 3 dBA nor would it exceed 60 dBA. Therefore, project impacts with respect to
exterior traffic noise would be less than significant.
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Interior Traffic Noise. The proposed project would be designed to meet or exceed
California Energy Code Title 24 standards, which specify construction methods and materials
that result in energy efficient structures and up to a 30 dBA reduction in exterior noise levels
(assuming windows are closed). When windows are open the insertion loss drops to about 10
dBA. Assuming that windows are closed, interior noise levels associated with traffic operations
would be reduced from 58 dBA to 28 dBA, which would be below the 45 dBA standard.
Exterior Railroad Noise. The AT&SF corridor is located approximately 350 feet to the
west of the site and is used by Amtrak and the North County Transit District Coaster to provide
passenger rail service. It is also used by freight trains during the late evening and nighttime
hours. Based on the time tables, approximately 50 trains operate daily within this segment.
Train volumes vary throughout the day, but are generally higher during the morning and
evening commute hours and reflect the dominant use of this corridor by commuter rail and
passenger trains.
Train noise is generated by a combination of factors, including the number of locomotives, rail
cars, speed, volume distribution over the day and nighttime hours and whether train horns are
used. The existing rail noise levels at the project site were calculated using a proprietary
software program developed by Rincon Consultants. Because Coaster trains stop at the
Carlsbad station (Amtrak and freight trains do not), which is located approximately 2 blocks
north of Carlsbad Village Drive, it was assumed the average speed through the area is 35 miles
per hour. It was assumed that each passenger train has one locomotive and 10 rail cars. It was
assumed that each freight train has have two locomotives and 50 cars. All trains are assumed to
use the warning horn when approaching/ crossing Carlsbad Village Drive. Of the 50 train pass
by events each day, five freight operations were assumed to occur during the nighttime (10:00
p.m. to 7:00 a.m.) hours. Based on these assumptions, the exterior CNEL at the project site
(located 350 east of the rail corridor) is approximately 62.8 dBA when both passenger and
freight rail operations are combined. This does not consider intervening buildings that may
reduce noise levels by approximately 5 dBA 'for first floor/single story receivers. Thus, existing
noise levels exceed the 60 dB CNEL recommended in the General Plan Noise Element for
residential areas within the City of Carlsbad. The CNEL calculated for rail operations by this
methodology is generally consistent with the 65 dBA contour line shown in the General Plan.
Interior Railroad Noise. While the proposed project would have no impact on rail noise,
the CNEL at the project site currently exceeds 60 dBA. Thus, project design features would be
necessary to reduce interior noise levels to at least 45 dBA CNEL as specified in the City of
Carlsbad Noise Guidelines Manual. As noted above, the proposed project would be designed to
meet or exceed California Energy Code Title 24 standards which specify construction methods
and materials that result in energy efficient structures and up to a 30 dBA reduction in exterior
noise levels (assuming windows are closed). Assuming windows are closed, the CNEL
associated with rail noise would be reduced from 62.8 dBA CNEL to 32.8 dBA CNEL, which
would be consistent with City standards. No measures in addition to compliance with Title 24
design requirements would be necessary to reduce rail noise.
Rail Vibration. The proposed project would be constructed approximately 350 feet east
of the rail corridor. Thus, a screening evaluation of potential vibration impacts was performed
to determine whether the project would be exposed to vibration levels that could be perceived
by building residents. The proposed residential project would be considered a Category 2 land r City of Carlsbad
12
The Wave Mixed Use Development Project
Noise Impact Study
use for the purposes of vibration assessment as defined in the Federal Transit Administration,
Transit Noise and Vibration Impact Assessment (2006). This category covers all residential land
uses and any buildings where people sleep, such as hotels and hospitals.
The impact criteria for a Category 2 land use is 75 V dB along corridors where train vibration
events occur occasionally (i.e., 30 to 70 events daily). A vibration velocity of 75 VdB is the
approximate dividing line between barely perceptible and distinctly perceptible levels.
A screening level evaluation was performed to determine the likelihood of vibrations from the
LOSSAN corridor affecting the proposed project. The screening distance for conventional
commuter railroads was used to account for both passenger and freight trains. The distance
between a conventional commuter railroad and Category 2 land use where the potential for a
vibration impact to occur is 200 feet as defined in Table 9.2 within the FTA noise and vibration
impact assessment methodology. The screening distances include a 5-decibel safety factor. The
project site is located beyond the 200-foot screening distance; thus, vibration-related impacts are
not anticipated and a more formal evaluation is not warranted.
r City of Carlsbad
13
The Wave Mixed Use Development Project
Noise Impact Study
REFERENCES
City of Carlsbad. General Plan Noise Element. 1993.
City of Carlsbad. Noise Guidelines Manual. September, 1995.
Federal Highway Administration. Roadway Construction Noise Model. 2006. Users Guide Table 1.
Federal Highway Administration, Transportation Noise Model Version 2.5, 2004.
Federal Transit Administration. Transit Noise and Vibration Impact Assessment. May 2006.
Federal Rail Administration (FRA) Guidelines (Report Number 293630-1), December 1998.
Hanson, Carl E., Towers, David A., and Meister, Lance D. (2006, May). Transit Noise and
Vibration Impact Assessment. Federal Transit Administration, Office of Planning and
Environment.
http://www.fta.dot.gov/documents/FTA Noise and Vibration Manual.pd£
Harris Miller Miller & Hanson Inc. Transit Noise and Vibration Impact Assessment, Final Report. May
2006.
Institute of Transportation Engineers (ITE) publication Trip Generation, 9th Edition
r City of Carlsbad
14
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RESULTS: SOUND LEVELS
City of Carlsbad
Rincon Consultants
RESULTS: SOUND LEVELS
PROJECT/CONTRACT:
RUN:
BARRIER DESIGN:
<Project Name?>
The Wave Mixed Use Project
INPUT HEIGHTS
<Project Name?>
20 July 2015
TNM2.5
Calculated with TNM 2.5
Average pavement type shall be used unless
a State highway agency substantiates the use
. --··--·--·-···----------____ of a differunt type with approval of FHWA, ~-~~~ I --ATMOSPHERICS:
..•.•.....• -·········--··-··-····-·-······-···· ····· ·····-······-···· ······ ·--··--········---··-·--··-·····----·-···-··--------·---Receiver ~-·-·-·-···--·-········· ············----······-·-·-····· ···········T---·--:----r············-:-::-,---· . ··-·----······----··-······--········-··---Name 1No. l#DUs !Existing 1No Barrier !With Barrier
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C:\TNM25\Program\The Wave Existing 1 20July 2015
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RESULTS: SOUND LEVELS
City of Carlsbad
Rincon Consultants
RESULTS: SOUND LEVELS
PROJECT/CONTRACT:
RUN:
BARRIER DESIGN:
<Project Name?>
The Wave Mixed Use Project
INPUT HEIGHTS
<Project Name?>
20July2015
TNM2.5
Calculated with TNM 2.5
Average pavement type shall be used unleaa
a State highway agency substantiates the use
ATMOSPHERICS: ---·---··----------68 deg F, 50% RH------·--·-···-···-----··--·--·-··------------of a_dlfferent type.wlth_.approval of FHWA.. ·----------·-··
Receiver
Nuno r-r· 1= r~:::-!~_,~==1=~~~t°.""-1::.E:~:~~~~-;c: .... -·-·· -·-·------------·---··-···-· -U· --1,BA l,BA ---k. .j.. ----E'"""l i--J~ __ k_ __ J~~ .. .
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C:\TNM25\Program\The Wave w-Project 1 20 July 2015
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