HomeMy Public PortalAbout4e-NoisevibrationNOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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E. NOISE AND VIBRATION
This section describes existing noise conditions in the Truckee Railyard Master Plan Area,
describes criteria for determining the significance of noise impacts, and estimates the likely
noise that would result from implementation of the Master Plan. Where appropriate,
mitigation measures are recommended to reduce project-related noise impacts to a less-
than-significant level.
1. Setting
The setting section begins with an introduction to several key concepts and terms that are
used in evaluating noise. It then explains the various agencies that regulate the noise
environment in the Town of Truckee and summarizes key standards that are applied to
proposed development. This setting section concludes with a description of current noise
sources that affect the Railyard Master Plan Area and the noise conditions that are
experienced in the vicinity.
a. Characteristics of Sound. Noise is generally defined as unwanted sound. Noise
consists of any sound that may produce physiological or psychological damage and/or
interfere with communication, work, rest, recreation, and sleep.
To the human ear, sound has two significant characteristics: pitch and loudness. Pitch is the
number of complete vibrations or cycles per second of a wave that results in the range of
tone from high to low. Loudness is the strength of a sound that describes a noisy or quiet
environment, and it is measured by the amplitude of the sound wave. Loudness is
determined by the intensity of the sound waves combined with the reception characteristics
of the human ear. Sound intensity refers to how hard the sound wave strikes an object,
which in turn produces the sound’s effect. This characteristic of sound can be precisely
measured with instruments. The analysis of a project defines the noise environment of the
Plan Area in terms of sound intensity and its effects on adjacent sensitive land uses.
(1) Measurement of Sound. Sound intensity is measured through the A-weighted
scale to correct for the relative frequency response of the human ear. That is, an A-weighted
noise level de-emphasizes low and very high frequencies of sound similar to the human
ear’s de-emphasis of these frequencies. Unlike linear units such as inches or pounds,
decibels are measured on a logarithmic scale, representing points on a sharply rising curve.
Table IV.E-1 contains a list of typical acoust ical terms and definitions. Table IV.E-2 shows
representative outdoor and indoor noise levels in units of dBA.
A decibel (dB) is a unit of measurement which indicates the relative intensity of a sound. The
0 point on the dB scale is based on the lowest sound level that the healthy, unimpaired
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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Table IV.E-1 Definitions of Acoustical Terms
Term Definitions
Decibel, dB
A unit of level that denotes the ratio between two quantities proportional to
power; the number of decibels is 10 times the logarithm (to the base 10) of
this ratio.
Frequency, Hz Of a function periodic in time, the number of times that the quantity repeats
itself in one second (i.e., number of cycles per second).
A-Weighted Sound
Level, dBA
The sound level obtained by use of A-weighting. The A-weighting filter de-
emphasizes the very low and very high frequency components of the sound in
a manner similar to the frequency response of the human ear and correlates
well with subjective reactions to noise. All sound levels in this report are A-
weighted, unless reported otherwise.
Equivalent Continuous
Noise Level, Leq
The level of a steady sound that, in a stated time period and at a stated
location, has the same A-weighted sound energy as the time varying sound.
Community Noise
Equivalent Level, CNEL
The 24-hour A-weighted average sound level from midnight to midnight,
obtained after the addition of five decibels to sound levels occurring in the
evening from 7:00 p.m. to 10:00 p.m. and after the addition of 10 decibels to
sound levels occurring in the night between 10:00 p.m. and 7:00 a.m.
Day/Night Noise Level,
Ldn
The 24-hour A-weighted average sound level from midnight to midnight,
obtained after the addition of 10 decibels to sound levels occurring in the
night between 10:00 p.m. and 7:00 a.m.
Lmax, Lmin The maximum and minimum A-weighted sound levels measured on a sound
level meter, during a designated time interval, using fast time averaging.
Single-Event Noise
Exposure Level, SENEL
The sound exposure level of a single noise event (such as an aircraft flyover
or a truck passby) measured over the time interval between the initial and
final times for which the sound level of the single-event exceeds the
background noise level.
Sound Exposure Level,
SEL
Ten times the common logarithm of the ratio of the sound exposure over a
stated time period to the reference sound exposure of 400 micro-pascal-
squared seconds.
Ambient Noise Level
The all encompassing noise associated with a given environment at a
specified time, usually a composite of sound from many sources at many
directions, near and far; no particular sound is dominant.
Intrusive
The noise that intrudes over and above the existing ambient noise at a given
location. The relative intrusiveness of a sound depends upon its amplitude,
duration, frequency, and time of occurrence and tonal or informational
content as well as the prevailing ambient noise level.
Source: Handbook of Acoustical Measurements and Noise Control, 1991.
NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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Table IV.E-2 Typical A-Weighted Sound Levels
Noise Source
A-Weighted
Sound Level in
Decibels Noise Environments
Near Jet Engine 140 Deafening
Civil Defense Siren 130 Threshold of pain
Hard Rock Band 120 Threshold of feeling
Accelerating Motorcycle at a Few Feet Away 110 Very loud
Pile Driver; Noisy Urban Street/Heavy City
Traffic 100 Very loud
Ambulance Siren; Food Blender 95 Very loud
Garbage Disposal 90 Very loud
Freight Cars; Living Room Music 85 Loud
Pneumatic Drill; Vacuum Cleaner 80 Loud
Busy Restaurant 75 Moderately loud
Near Freeway Auto Traffic 70 Moderately loud
Average Office 60 Moderate
Suburban Street 55 Moderate
Light Traffic; Soft Radio Music in Apartment 50 Quiet
Large Transformer 45 Quiet
Average Residence Without Stereo Playing 40 Faint
Soft Whisper 30 Faint
Rustling Leaves 20 Very faint
Human Breathing 10 Very faint
Source: Compiled by LSA Associates, Inc., 2007.
human ear can detect. Changes of 3 dB or less are only perceptible in laboratory
environments. Audible increases in noise levels generally refer to a change of 3 dB or more,
as this level has been found to be barely perceptible to the human ear in outdoor
environments. Sound levels in dB are calculated on a logarithmic basis. An increase of 10 dB
represents a 10-fold increase in acoustic energy, while 20 dB is 100 times more intense, 30
dB is 1,000 times more intense. Each 10-dB increase in sound level is perceived as
approximately a doubling of loudness.
As noise spreads from a source, it loses energy so that the farther away the noise receiver is
from the noise source, the lower the perceived noise level would be. Geometric spreading
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E. NOISE AND VIBRATION
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causes the sound level to attenuate or be reduced, resulting in a 6 dB reduction in the noise
level for each doubling of distance from a single point source of noise to the noise sensitive
receptor of concern.
There are many ways to rate noise for various time periods, but an appropriate rating of
ambient noise affecting humans also accounts for the annoying effects of sound. Equivalent
continuous sound level (Leq) is the total sound energy of time varying noise over a sample
time period. The predominant rating scales for human communities in the State of
California are the Leq, the community noise equivalent level (CNEL), and the day-night
average level (Ldn) based on A-weighted decibels (dBA). CNEL is the time varying noise over
a 24-hour period, with a 5 dBA weighting factor applied to the hourly Leq for noises
occurring from 7:00 p.m. to 10:00 p.m. (defined as relaxation hours) and 10 dBA weighting
factor applied to noise occurring from 10:00 p.m. to 7:00 a.m. (defined as sleeping hours).
Ldn is similar to the CNEL scale, but without the adjustment for events occurring during the
evening relaxation hours. CNEL and Ldn are within one dBA of each other and are normally
exchangeable. The noise adjustments are added to the noise events occurring during the
more sensitive hours. Typical A-weighted sound levels from various sources are described in
Table IV.E-2.
Other noise rating scales of importance when assessing the annoyance factor include the
maximum noise level (Lmax) and the single-event noise exposure level (SENEL). The Lmax
noise level is the highest exponential time averaged sound level that occurs during a stated
time period. The noise environments discussed in this analysis are specified in terms of
maximum levels denoted by Lmax for short-term noise impacts. Lmax reflects peak
operating conditions, and addresses the annoying aspects of intermittent noise. The SENEL,
or single-event noise exposure level, is an accumulation of the sound energy over the
duration of an event (such as a single aircraft fly-over), where duration is defined as the
period from when the A-weighted sound level first exceeds a background level to when the
sound level drops back below the background. This is functionally equivalent to the sound
exposure Level (SEL).
Noise impacts can be described in three categories. The first is audible impacts that refer to
increases in noise levels noticeable to humans. Audible increases in noise levels generally
refer to a change of 3.0 dBA or greater, since, as described earlier, this level has been found
to be barely perceptible in exterior environments. The second category, potentially audible,
refers to a change in the noise level between 1.0 and 3.0 dBA. This range of noise levels has
been found to be noticeable only in laboratory environments. The last category is changes
in noise level of less than 1.0 dBA that are inaudible to the human ear. Only audible changes
in existing ambient or background noise levels are considered potentially significant.
(2) Physiological Effects of Noise. Physical damage to human hearing begins at
prolonged exposure to noise levels higher than 85 dBA. Exposure to high noise levels
NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
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E. NOISE AND VIBRATION
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affects our entire system, with prolonged noise exposure in excess of 75 dBA increasing
body tensions, and thereby affecting blood pressure, functions of the ear, and the nervous
system. In comparison, extended periods of noise exposure above 90 dBA would result in
permanent cell damage. When the noise level reaches 120 dBA, a tickling sensation occurs
in the human ear even with short-term exposure. This level of noise is called the threshold
of feeling.
Sleep disturbance caused by noise is variable and difficult to characterize because of the
difficulty in determining the quality of sleep. In general, the relationship of human response
to noise during sleep is determined using the noise metric of the “sound exposure level”
(SEL) and an estimated “percent awakening” caused by the noise. A guideline for
determining sleep disturbance is that awakening may occur for a maximum 10 percent of
the population when the indoor sound level exceeds 80 dB SEL. This equates to when the
outdoor sound level associated with a single-event exceeds 95 dB SEL if windows are open
or 105 dB with windows closed.
b. Characteristics of Groundborne Vibration. Vibrating objects in contact with the
ground radiate vibration waves through various soil and rock strata to the foundations of
nearby buildings. As the vibration propagates from the foundation throughout the
remainder of the building, the vibration of floors and walls may cause perceptible vibration
from the rattling of windows or a rumbling noise. The rumbling sound caused by the
vibration of room surfaces is called groundborne noise. When assessing annoyance from
groundborne noise, vibration is typically expressed as root mean square (rms) velocity in
units of decibels of 1 micro-inch per second. To distinguish vibration levels from noise
levels, the unit is written as “VdB.” Human perception to vibration starts at levels as low as
67 VdB and sometimes lower. Annoyance due to vibration in residential settings starts at
approximately 70 VdB. Groundborne vibration is almost never annoying to people who are
outdoors. Although the motion of the ground may be perceived, without the effects
associated with the shaking of the building, the motion does not provoke the same adverse
human reaction.
In extreme cases, excessive groundborne vibration has the potential to cause structural
damage to buildings. The threshold for minor cosmetic damage of buildings considered of
particular historical significance or that are particularly fragile structures is approximately
96 VdB; the damage threshold for other structures is 100 VdB.1 Common sources of
groundborne vibration include trains and construction activities such as blasting, pile
driving and operating heavy earthmoving equipment. Typical vibration source levels from
construction equipment are shown in Table IV.E-3.
1 Harris, C.M. 1998. Handbook of Acoustical Measurements and Noise Control.
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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c. Noise Regulatory Framework. The
following section summarizes the regulatory
framework related to noise, including
federal, State, and Town of Truckee plans,
policies and standards.
(1) U.S. Environmental Protection
Agency (EPA). In 1972 Congress enacted
the Noise Control Act. This act authorized
the EPA to publish descriptive data on the
effects of noise and establish levels of sound
“requisite to protect the public welfare with
an adequate margin of safety.” These levels
are separated into health (hearing loss
levels) and welfare (annoyance levels), as
shown in Table IV.E-4. The EPA cautions that
these identified levels are not standards
because they do not take into account the
cost or feasibility of the levels.
For protection against hearing loss, 96
percent of the population would be pro-
tected if sound levels are less than or equal
to an Leq(24) of 70 dB. The “(24)” signifies
an Leq duration of 24 hours. The EPA activity
and interference guidelines are designed to
ensure reliable speech communication at
about 5 feet in the outdoor environment. For
outdoor and indoor environments,
interference with activity and annoyance
should not occur if levels are below 55 dBA
and 45 dBA, respectively.
The noise effects associated with an outdoor
Ldn of 55 dB are summarized in Table IV.E-
5. At 55 dB Ldn, 95 percent sentence clarity
(intelligibility) may be expected at 3.5
meters, and no community reaction.
However, 1 percent of the population may
complain about noise at this level and 17
percent may indicate annoyance.
Table IV.E-3 Typical Vibration Source Levels
for Construction Equipment
Equipment
Approximate
VdB at 25
Feet
Upper range 112 Pile Driver (impact)
Typical 104
Upper range 105 Pile Driver (sonic)
Typical 93
Clam shovel drop (slurry wall) 94
In soil 66 Hydromill (slurry wall)
In rock 75
Vibratory roller 94
Hoe ram 87
Large bulldozer 87
Caisson drilling 87
Loaded trucks 86
Jackhammer 79
Small bulldozer 58
Source: Federal Transit Administration, 2006. Transit Noise
and Vibration Impact Assessment. May.
Table IV.E-4 Summary of EPA Noise Levels
Effect Level Area
Hearing
loss
Leq(24) < 70
dB All areas.
Outdoor
activity
interference
and
annoyance
Ldn < 55 dB
Outdoors in residential
areas and farms and
other outdoor areas
where people spend
widely varying amounts
of time and other
places in which quiet is
a basis for use.
Leq(24) < 55
dB
Outdoor areas where
people spend limited
amounts of time, such
as school yards, play-
grounds, etc.
Leq < 45 dB Indoor residential
areas.
Indoor
activity
interference
and
annoyance
Leq(24) < 45
dB
Other indoor areas
with human activities
such as schools, etc.
Source: U.S. Environmental Protection Agency, 1974.
“Information on Levels of Environmental Noise Requisite to
Protect Public Health and Welfare with an Adequate Margin
of Safety.” March.
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E. NOISE AND VIBRATION
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(2) State of California. The
State of California has established
regulations that help prevent adverse
impacts to occupants of buildings
located near noise sources. Referred to
as the “State Noise Insulation
Standard,” it requires buildings to meet
performance standards through design
and/or building materials that would
offset any noise source in the vicinity
of the receptor. State regulations
include requirements for the
construction of new hotels, motels,
apartment houses, and dwellings other
than detached single-family dwellings
that are intended to limit the extent of
noise transmitted into habitable
spaces. These requirements are found
in the California Code of Regulations,
Title 24 (known as the Building
Standards Administrative Code), Part 2
(known as the California Building
Code), Appendix Chapters 12 and 12A.
For limiting noise transmitted between
adjacent dwelling units, the noise insulation standards specify the extent to which walls,
doors, and floor ceiling assemblies must block or absorb sound. For limiting noise from
exterior noise sources, the noise insulation standards set an interior standard of 45 dBA
CNEL in any habitable room with all doors and windows closed. In addition, the standards
require preparation of an acoustical analysis demonstrating the manner in which dwelling
units have been designed to meet this interior standard, where such units are proposed in
an area with exterior noise levels greater than 60 dBA CNEL.
The State has also established land use compatibility guidelines for determining acceptable
noise levels for specified land uses. The Town has adopted and modified the State’s land
use compatibility guidelines, as shown in Table IV.E-6, and as discussed below.
(3) Town of Truckee. The Town of Truckee addresses noise in the Noise Element of
the General Plan2 and in Chapter 18.44 of the Municipal Code.3 The Town’s policies address
2 Truckee, Town of, 2007. Town of Truckee 2025 General Plan.
3 Truckee, Town of, 2004. Municipal Code. September.
Table IV.E-5 Summary of Human Effects in
Areas Exposed to 55 dBA Ldn
Type of
Effects Magnitude of Effect
Speech –
Indoors
100 percent sentence intelligibility
(average) with a 5 dB margin of
safety.
Speech –
Outdoors
100 percent sentence intelligibility
(average) at 0.35 meters.
99 percent sentence intelligibility
(average) at 1.0 meters.
95 percent sentence intelligibility
(average) at 3.5 meters.
Average
Community
Reaction
None evident; 7 dB below level of
significant complaints and threats
of legal action and at least 16 dB
below “vigorous action.”
Complaints 1 percent dependent on attitude
and other non-level related factors.
Annoyance 17 percent dependent on attitude
and other non-level related factors.
Attitude
Towards Area
Noise essentially the least
important of various factors.
Source: U.S. Environmental Protection Agency, 1974.
“Information on Levels of Environmental Noise Requisite to
Protect Public Health and Welfare with an Adequate Margin
of Safety.” March.
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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Table IV.E-6 Land Use Compatibility Guidelines
Exterior Noise Exposure (CNEL, dB)a
Land Use Category 55 60 65 70 75 80
Residential, Mobile Homes
Residential in Mixed Use
Development
Hospitals, Schools, Congregate
Care
Office, Medical;
Light Industrial
Hotel; Commercial
Neighborhood Parks, RV Parks
Other Recreation; Community and
Regional Parks
a Based on worst-case levels, both existing and 2025.
Note: the Truckee-Tahoe Airport has separate guidelines addressing airport noise.
NORMALLY ACCEPTABLE
Specified land use is compatible, assuming standard
construction practices are used.
NORMALLY UNACCEPTABLE
New land uses should be discouraged, but development
may be allowed after a detailed noise analysis is
performed, noise reduction and insulation features
necessary to reduce exterior noise to “normally acceptable”
levels and interior noise levels as appropriate are included
in project design, and the land uses are shown to serve the
greater public interests of the citizens of Truckee.
CONDITIONALLY ACCEPTABLE
New land uses may be allowed if detailed noise analysis is
performed and noise reduction and insulation features
necessary to reduce exterior noise levels to “normally
acceptable” levels and interior noise levels as appropriate
are included in the project design.
UNACCEPTABLE
New construction or development of these land uses
should generally not be permitted because mitigation is
usually not feasible.
Source: Town of Truckee, 2007. Town of Truckee 2025 General Plan. Figure N-3.
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The noise level requirements for new development. The Town’s policies extend the
California Noise Insulation Standards for interior noise levels attributable to exterior sources
to all proposed new single-family residences. The policies of the Noise Element that are
applicable to the proposed Railyard Master Plan are provided below.
Policies
P1.2: Require new development to mitigate exterior noise to “normally acceptable” levels in
outdoor areas where quiet is a benefit, such as in the backyards of single-family homes.
P1.3: Enforce the California Noise Insulation Standards for interior noise levels attributable to
exterior sources for all proposed new single- and multi-family residences.
P1.7: Reduce potential impacts from goundborne vibration associated with rail operations by
requiring that vibration-sensitive buildings (e.g., residences) are sited at least 100 feet from the
centerline of the railroad tracks whenever feasible and that development of vibration-sensitive
buildings within 100-feet from the centerline of the railroad tracks require a study demonstrating
that groundborne vibration issues associated with rail operations have been adequately addressed
(i.e., through building siting or construction techniques).
The Municipal Code includes the following ordinances governing stationary noise sources
that are applicable to the proposed project.
18.44.040 - Exterior Noise Standards: It shall be unlawful for any person, at any location within
the Town, to create any noise or to allow the creation of any noise on property leased, occupied,
owned, or otherwise controlled by the person which does not comply with the provisions of this
Section, unless the provisions of either Sections 18.44.050 (Residential Interior Noise Standards)
or 18.44.070 (Exceptions), below have been met.
A. Exterior levels: Exterior noise levels, when measured at any receiving church, commercial,
hospital, public library, residential or school property, do not conform to the provisions of this
Section when they exceed the noise level standards established by Table 3-8 (reference
Table IV.E-7).
B. Ambient Noise Level Adjustment: In the event the measured ambient noise level exceeds
the applicable noise level standard in any category above, the applicable standards shall be
adjusted to equal the ambient noise level. For example, if the applicable noise level standard
is 60 dB(A) and the ambient noise level is 63 dB(A), the applicable noise level standard would
be adjusted to 63 dB(A). In these cases, a use would not exceed the applicable noise level
standard if it did not increase the ambient noise level by more than 3.0 dB(A) when the
ambient noise level is between 60 and 65 dB(A) or by more than 1.5 dB(A) when the ambient
noise level is greater than 65 dB (A).
F. Commercial/Industrial Exterior Noise Standard: Whenever a new office, commercial,
hotel/motel, or light industrial use is proposed on a parcel where the existing ambient noise
levels may exceed 70 dB(A) CNEL, the land use permit application shall include an acoustical
analysis of the affect of noise sources on the use. The acoustical analysis shall identify
appropriate mitigation measures that reduce noise levels to acceptable levels. These
mitigation measures shall be incorporated into the design, construction, and operation of the
use. Office, commercial, hotel/motel, and light industrial uses that cannot mitigate noise
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Table IV.E-7 Noise Standard by Receiving Land Use
Noise Level Standards, dBA
Cumulative Number
of Minutes in Any
Hour
Day – 7:00 a.m.
to 10:00 p.m.
Night – 10:00 p.m.
to 7:00 a.m.
Hospital, Library, Religious Institutions, Residential, or School
Uses
30 a 55 50
15 60 55
5 65 60
1 70 65
0 75 70
Commercial Uses
30 65 60
15 70 65
5 75 70
1 80 75
0 85 80
a For example, this means the measured noise level may not exceed 55 dBA for
more than 30 minutes out of any one hour time period.
Source: Town of Truckee, 2004. Municipal Code, Chapter 18.44, Table 3-8.
September.
levels to "Normally Acceptable" levels as defined in Table 6.1 of the General Plan shall not be
approved.
G. Public/Institutional Exterior Noise Standard: Whenever a hospital, library, school,
congregate care, or similar public or institutional use is proposed on a parcel where the
existing ambient noise levels may exceed 65 dB(A) CNEL, the land use permit application shall
include an acoustical analysis of the affect of noise sources on the use. The acoustical analysis
shall identify appropriate mitigation measures that reduce noise levels to acceptable levels.
These mitigation measures shall be incorporated into the design construction, and operation
of the use. Public and institutional uses that cannot mitigate noise levels to "Normally
Acceptable" levels as defined in Table 6.1 of the General Plan shall not be approved.
H. Sensitive land uses: Whenever a use is proposed on a parcel where the expected noise
levels generated by the use, when measured at any receiving church, hospital, public library,
residential, or school property, may exceed the noise level standards established by Table 3-8
(reference Table 7), the land use permit application shall include an acoustical analysis of the
affect of the noise generated by the use on the sensitive land use property. An acoustical
analysis shall also be required when a commercial or industrial loading dock or area is located
within 300 feet of a sensitive use. The acoustical analysis shall identify appropriate mitigation
measures that reduce exterior noise levels to acceptable levels established by Table 3-8
(reference Table 7). These mitigation measures shall be incorporated into the design,
construction, and operation of the use.
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I. Mitigation: Reasonable noise mitigation measures including building setbacks, alternative
site design techniques, and alternative building orientation layouts shall be employed in lieu
of sound walls to mitigate noise impacts. Sound walls may be used if there are no other
reasonable mitigation measures available or all reasonable mitigation measures do not
satisfactorily reduce noise levels to acceptable levels.
The Municipal Code further includes ordinances governing mobile noise sources that are
applicable to the proposed project as outlined below.
18.44.050 - Residential Interior Noise Standards: Single-family and multi-family residential
development shall be designed and constructed to comply with the interior noise standards of this
Section.
A. Interior Noise Standard: Whenever a new single-family or multi-family dwelling unit is
proposed on a parcel where the existing exterior ambient noise level may exceed 60 dB(A)
CNEL, the land use permit application shall include an acoustical analysis showing the
dwelling unit has been designed to limit intruding noise to an interior CNEL of 45 dB(A), in
compliance with California Code of Regulations Title 24, Part 2.
B. Residential Development Affected by Aircraft Noise: Land use permit applications for
residential structures proposed within the Airport 55 dB(A) CNEL contour shall comply with
the provisions of Section 18.64.060 (Airport Noise Zones).
C. Noise Mitigation Measures: Whenever interior noise levels may exceed 45 dB(A) CNEL,
residential developments shall incorporate the following noise mitigation measures, where
appropriate:
- 1. Increase the distance between the noise source and the receiver;
- 2. Locate bedrooms on the side of the structure away from major public rights-of-way;
and/or
- 3. Locate land uses not sensitive to noise (e.g., garages, maintenance facilities, parking
lots, utility areas, etc.) between the noise source and the receiver.
• D. Noise barrier standards: The minimum acceptable surface weight for a noise barrier is four
pounds per square foot (equivalent to three-fourths inch plywood). Noise barriers shall
interrupt the line-of-sight between the noise source and the receiver. The barrier shall be of a
continuous material which is resistant to sound and may including the following:
- 1. Earth berm or a combination of earth berm with concrete block; or
- 2. Masonry block; or
- 3. Precast concrete.
18.44.070 - Exceptions.
A. Construction: The provisions of this Chapter shall not apply to noise sources associated
with non-single family residential construction, provided the activities do not take place
before 7:00 a.m. or after 9:00 p.m. on any day except Sunday, or before 9:00 a.m. or after
6:00 p.m. on Sunday. The review authority may impose further limitations on the hours of
construction or other measures to mitigate significant noise impacts on sensitive uses.
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
C:\JOB\RRM\Truckee\PublicReviewDraft_Oct08\4e-Noisevibration.doc (11/3/2008) 230
G. Public transportation facilities. The provisions of this Section shall not apply to any
airports, railroad facilities including but not limited to trains, rolling stock, and railroad
equipment, publicly owned roads and right-of-ways, or other similar facilities.
d. Existing Noise Environment. The following section describes the existing noise
environment and identifies primary noise sources in each of the component areas of the
Plan.
(1) Existing Conditions. The Plan Area is currently bordered by undeveloped land to
the north along Glenshire Drive, a landscaping business to the east, by the Union Pacific
Railroad tracks and East River Street to the south, and Donner Pass Road and Brockway Road
to the west. Existing land uses within and adjacent to the Plan Area include the Railyard (a
railroad operations building, balloon track and storage tracks), eight homes, Tahoe Tree
Company, Tahoe-Truckee Lumber Company, a glazier, a card-lock fueling facility, and Trout
Creek.
An LSA technician conducted 48-hour ambient noise monitoring in the proposed Plan Area
from November 16 to November 18, 2006. The purpose of this noise monitoring was to
document the existing noise environment and capture the noise levels associated with
operations and activities in the Plan vicinity, including roadway and railroad noise sources.
Maximum and minimum noise levels
were recorded as well as the equivalent
continuous noise level measure Leq.
The CNEL value was calculated from
the hourly Leq values. Table IV.E-8 lists
the noise levels measured and
calculated during field monitoring. The
noise monitoring location is shown in
Figure V.E-1 and a chart of the 48-hour measured and calculated noise levels is shown in
Figure IV.E-2. This measurement captures both typical weekday and weekend ambient noise
conditions in the project vicinity.
These noise measurements are used in the following analysis for comparative purposes to
the modeling results, to demonstrate correlation between modeled and existing measured
conditions, as well as to document existing baseline ambient noise environment conditions.
(2) Existing Railroad Noise Sources. The proposed Plan Area would be located
adjacent to the Union Pacific Railroad tracks and would include the relocation of the balloon
track to the eastern portion of the development area. Railroad activities in this area
significantly affect the ambient noise environment. The railroad has freight and passenger
Table IV.E-8 Ambient Noise Monitoring
Results, dBA
Measured Calculated
CNEL Leq Lmax Lmin
69 59 106.6 39.4
Source: LSA Associates, Inc., May, 2008.
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NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
C:\JOB\RRM\Truckee\PublicReviewDraft_Oct08\4e-Noisevibration.doc (11/3/2008) 233
trains that generate intermittent loud sounds during passbys. Noise generated by an
individual train depends on the train type, length, speed, and whether the train uses its
warning whistle. Trains are required to sound their warning whistles near “at-grade”
crossings to warn motorists of the on-coming train. There is an existing at-grade crossing at
Bridge Street at the western boundary of the Plan Area. According to the Noise Technical
Appendix of the Truckee 2025 General Plan EIR,4 noise levels at a distance of 100 feet from
the railroad are approximately 76 dBA CNEL. This level includes all railroad-related noise,
including train horns. As documented by the long-term ambient noise measurement, the
ambient noise level within the Plan Area is 69 dBA CNEL, measured at a distance of
approximately 200 feet from the railroad centerline. Thus the measured ambient noise level
shows strong correlation to the railroad noise levels documented in the Town’s General
Plan. The documented maximum noise levels within the Plan Area of up to 106.6 dBA all
reflect railroad activities (including train pass-bys, warning whistles, and idling).
(3) Existing Aircraft Noise Sources. The Plan Area is located within the influence
area of the Truckee-Tahoe Airport and is subject to the land use regulations of the Airport
Land Use Compatibility Plan. Truckee-Tahoe Airport is located approximately 1 mile
southeast of the Plan Area. According to the future airport noise contours, Figure 2B of the
Truckee Tahoe Airport Land Use Compatibility Plan,5 the 60 dBA CNEL airport noise contour
lies to the east of the Plan Area; however, the eastern portion of the Plan Area lies within the
55 dBA CNEL airport noise contour. These noise contours represent the points beyond
which airport related noise would attenuate to below the indicated noise level. These
contours reflect generalized noise projections, and do not take into account site specific
topography, natural vegetation, site orientation or other localized factors.
(4) Existing Traffic Noise Sources. Vehicular traffic is a major source of ambient
noise levels in urban settings. Interstate 80 (I-80) is the major transportation corridor
through the Town of Truckee. The Plan Area’s northwestern boundary lies within approxi-
mately 850 feet of the centerline of I-80. The ambient noise level measurement taken within
the Plan Area documented all noise sources within the vicinity, including freeway and rail-
road noise sources. In addition, all of the recorded maximum noise levels were from rail-
road noise sources. Noise from traffic sources on I-80 is reduced by distance attenuation
and topographical shielding to levels below approximately 65 dBA CNEL.
Existing baseline traffic noise levels along select roadway segments in the Plan vicinity were
modeled using the predicted traffic volumes for the Summer of 2008 without implemen-
tation of the proposed project. The results of the traffic noise modeling are shown in Table
IV.E-9 below. This table was generated from roadway traffic volumes data, vehicle speeds,
and roadway geometry, using the Federal Highways Administration (FHWA) Highway Traffic
4 Truckee, Town of, 2006. Town of Truckee 2025 General Plan EIR, Appendix B. November 16.
5 Truckee Tahoe Airport Land Use Compatibility Plan, December 2, 2004.
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
C:\JOB\RRM\Truckee\PublicReviewDraft_Oct08\4e-Noisevibration.doc (11/3/2008) 234
Table IV.E-9 Summer (2008) Baseline Traffic Noise Levels
Roadway Segment ADT a
Center-
line to
70 CNEL
(feet)
Center-
line to
65
CNEL
(feet)
Center-
line to
60
CNEL
(feet)
CNEL (dBA)
50 feet
from
Centerline
of
Outermost
Lane
Donner Pass Road - Spring Street to Bridge
Street 11,900 < 50 b 56 119 64.9
Donner Pass Road - Bridge Street to Church
Street 9,200 < 50 < 50 100 63.8
Donner Pass Road - Church Street to Keiser
Avenue 3,500 < 50 < 50 53 59.6
Bridge Street – north of Jibboom Street 500 < 50 < 50 < 50 51.2
Bridge Street - Jibboom Street to Church
Street 6,100 < 50 < 50 76 62.0
Brockway Road - south of East River Street 16,100 < 50 68 146 66.3
West River Street - west of Brockway Road 8,800 < 50 < 50 97 63.6
East River Street east of Brockway Road 1,200 < 50 < 50 < 50 55.0
a Average Daily Traffic.
b Traffic noise within 50 feet of the roadway centerline requires site-specific analysis.
Source: LSA Associates Inc., May 2008.
Noise Prediction Model. Existing summertime noise levels along these roadway segments (at
50 feet from the centerline of the outermost travel lane) range from 51.2 dBA CNEL to 66.3
dBA CNEL.
2. Relevant Railyard Draft Master Plan Policies
The Draft Master Plan does not include any specific policies related to noise or vibration.
3. Impacts and Mitigation Measures
This section analyzes the impacts related to noise and vibration that could result from
implementation of the Master Plan. This section begins with the criteria of significance
which establish the thresholds for determining whether a project impact is significant. The
latter part of this section presents the potential impacts and recommends mitigation
measures as appropriate.
a. Criteria of Significance. A project would have a significant noise effect if it would
substantially increase the ambient noise levels for adjoining areas or conflict with adopted
environmental plans and goals of the community in which it is located. The applicable noise
standards governing the Plan Area are the State’s noise criteria, the Town of Truckee’s
NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
C:\JOB\RRM\Truckee\PublicReviewDraft_Oct08\4e-Noisevibration.doc (11/3/2008) 235
Noise Element of the General Plan, and applicable sections of the Town’s Municipal Code.
For the purposes of this analysis, a project would result in a significant noise impact if it
would:
Expose persons to or generate noise levels in excess of normally acceptable standards
established in the local General Plan or noise ordinance, or applicable standards of other
agencies;
Expose persons to or generate excessive groundborne vibration or noise;
Result in a substantial permanent, temporary, or periodic increase in ambient noise
levels by more than 3 dBA in the project vicinity above levels existing without the project
if the ambient noise level is between 60 and 65 dBA or by more than 1.5 dBA if the
ambient noise level in the project vicinity is greater than 65 dBA; or
Expose people residing or working in the Plan Area to excessive aircraft noise levels.
The significance criteria identified above are based on Section 15065 and Appendix G of the
CEQA Guidelines.
b. Less-Than-Significant Noise Impacts. The less-than-significant noise effects
associated with the implementation of the Master Plan are described below.
(1) Aircraft Noise Sources. Aircraft related noise would be audible and would affect
noise sensitive land use development within the Plan Area. However, the Plan Area is located
outside of the 60 dBA CNEL airport noise contour with the exception of the eastern-most
portion of the Plan Area where the balloon track would be located. These noise contours
reflect generalized noise projections, and do not take into account site specific topography,
natural vegetation, site orientation or other localized factors. However, with implementation
of the preferred Plan including the relocating of the Union Pacific Railroad balloon track to
the eastern end of the Plan Area, noise sensitive development within the Plan Area would be
located further from the 60 dBA CNEL airport noise contour. Therefore, due to the distance
from and the flight path orientation to the airport, aircraft related noise impacts would be
considered a less-than-significant impact on noise sensitive development within the Plan
Area.
(2) Groundborne Noise and Vibration Impacts. Based on the criteria of
significance, a significant impact would occur if the project would expose persons to or
generate excessive groundborne vibration or noise levels. Human perception to vibration
starts at levels as low as 67 VdB and sometimes lower. Annoyance due to vibration in
residential settings starts at approximately 70 VdB. In extreme cases, excessive
groundborne vibration has the potential to cause structural damage to buildings. The
damage threshold for buildings considered of particular historical significance or that are
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
C:\JOB\RRM\Truckee\PublicReviewDraft_Oct08\4e-Noisevibration.doc (11/3/2008) 236
particularly fragile structures is approximately 96 VdB; the damage threshold for other
structures is 100 VdB.6
Common sources of ground-borne vibration include construction activities such as blasting,
pile driving and operating heavy earthmoving equipment. However, it is anticipated that
construction of projects within the Plan will not employ pile driving as a construction
method. Typical groundborne vibration levels measured at a distance of 50 feet from heavy
construction equipment in full operation, such as bulldozers or other heavy tracked
equipment, range up to approximately 94 VdB. This is below the damage threshold for
historic or fragile buildings. Furthermore, compliance with all of Truckee’s established
standard construction noise control measures would reduce construction-related
groundborne vibration impacts to a less-than-significant level.
Other sources of groundborne vibration include railroad activities. Residential land uses
could be located along the north side of the proposed Donner Pass Road Extension, as close
as 150 feet from the railroad tracks. Based on the Federal Transit Administration general
vibration assessment guidelines, groundborne vibration levels from locomotive powered
passenger or freight trains would produce approximately 69.6 VdB at a distance of 150 feet
when traveling at 30 mph. This is the predicted exterior vibration level, and does not
account for any additional dampening effects of the building structure for inside occupants.
This level would therefore be less than the damage threshold for any structure built within
the Plan Area and would also be less than the annoyance threshold of 70 VdB for residential
land uses. Railroad related groundborne vibration and noise sources would therefore be
considered a less-than-significant impact on sensitive land uses within the Plan Area.
(3) Traffic Noise Impacts. The FHWA highway traffic noise prediction model (FHWA
RD-77-108) was used to evaluate traffic-related noise conditions in the vicinity of the Plan
Area. The resultant noise levels were weighed and summed over a 24-hour period in order
to determine the CNEL values. The existing and future traffic volumes for roadway segments
in the project vicinity were used in the traffic noise impact analysis. Table IV.E-10 shows the
Summer 2008 Plus Project Traffic Noise Levels along modeled roadway segments in the Plan
Area. Tables IV.E-11 and IV.E-12 show the predicted Summer traffic noise levels for the year
2025 without and with the project, respectively.
A significant impact on off-site sensitive receptors would occur if project related traffic
noise levels would result in a substantial permanent increase in ambient noise levels of 3
dBA or greater if the ambient noise level is between 60 and 65 dBA or by more than 1.5 dBA
if the ambient noise level in the project vicinity is greater than 65 dBA. Based on the noise
monitoring results, the ambient noise level in the project vicinity is 69 dBA CNEL. Modeling
results indicate that only one roadway segment would experience a significant increase in
6 Harris, C.M. 1998. Handbook of Acoustical Measurements and Noise Control.
NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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Table IV.E-10 Summer (2008) Plus Project Traffic Noise Levels
Roadway Segment ADT a
Center-
line to
70 CNEL
(feet)
Center-
line to
65 CNEL
(feet)
Center-
line to
60 CNEL
(feet)
CNEL
(dBA) 50
feet from
Centerline
of
Outermost
Lane
Increase
from
Baseline
Conditions
Donner Pass Road - Spring Street to
Bridge Street 13,300 < 50 b 60 128 65.4 0.5
Donner Pass Road - Bridge Street to
Church Street 11,100 < 50 53 114 64.6 0.8
Donner Pass Road - Church Street to
Keiser Avenue 4,200 < 50 < 50 60 60.4 0.8
Bridge Street - north of Jibboom
Street 1,200 < 50 < 50 < 50 55.0 3.8
Bridge Street - Jibboom Street to
Church Street 7,700 < 50 < 50 89 63.1 1.1
Brockway Road - south of East River
Street 17,300 < 50 71 153 66.6 0.3
West River Street - west of Brockway
Road 9,800 < 50 < 50 105 64.1 0.5
East River Street east of Brockway
Road 1,300 < 50 < 50 < 50 55.3 0.3
a Average Daily Traffic.
b Traffic noise within 50 feet of the roadway centerline requires site-specific analysis.
Source: LSA Associates Inc., May 2008.
Table IV.E-11 Summer (2025) without Project Traffic Noise Levels
Roadway Segment ADT
Center-
line to
70 CNEL
(feet)
Center-
line to
65 CNEL
(feet)
Center-
line to
60 CNEL
(feet)
CNEL (dBA)
50 feet
from
Centerline
of
Outermost
Lane
Donner Pass Road - Spring Street to
Bridge Street 8,400 < 50 < 50 95 63.4
Donner Pass Road - Bridge Street to
Church Street 6,200 < 50 < 50 77 62.1
Donner Pass Road - Church Street to
Keiser Avenue 7,800 < 50 < 50 90 63.1
Bridge Street - north of Jibboom Street 9,200 < 50 < 50 100 63.8
Bridge Street - Jibboom Street to
Church Street 2,200 < 50 < 50 < 50 57.6
Brockway Road - south of East River
Street 21,100 < 50 81 174 67.4
West River Street - west of Brockway
Road 11,200 < 50 53 114 64.7
East River Street east of Brockway Road 1,600 < 50 < 50 < 50 56.2
Source: LSA Associates Inc., May 2008.
TRUCKEE RAILYARD DRAFT MASTER PLAN EIR NOVEMBER 2008
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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Table IV.E-12 Summer (2025) Plus Project Traffic Noise Levels
Roadway Segment ADT
Center-
line to
70 CNEL
(feet)
Center-
line to
65 CNEL
(feet)
Center-
line to
60 CNEL
(feet)
CNEL
(dBA) 50
feet from
Centerline
of
Outermost
Lane
Increase
from
Baseline
Conditions
Donner Pass Road - Spring Street to
Bridge Street 8,300 < 50 < 50 94 63.4 0.0
Donner Pass Road - Bridge Street to
Church Street 7,900 < 50 < 50 91 63.2 1.1
Donner Pass Road - Church Street to
Keiser Avenue 8,100 < 50 < 50 92 63.3 0.2
Bridge Street - north of Jibboom Street 9,700 < 50 < 50 104 64.1 0.3
Bridge Street - Jibboom Street to
Church Street 4,000 < 50 < 50 58 60.2 2.6
Brockway Road - south of East River
Street 21,200 < 50 81 175 67.5 0.1
West River Street - west of Brockway
Road 10,800 < 50 52 112 64.5 -0.2
East River Street east of Brockway
Road 1,600 < 50 < 50 < 50 56.2 0.0
Source: LSA Associates Inc., May 2008.
project-related traffic noise levels. The roadway segment of Bridge Street north of Jibboom
Street would experience an increase in traffic noise levels of up to 3.8 dBA under the
summer 2008 with project traffic scenario and up to 2.6 under the summer 2025 Plus
Project conditions. This is above the Town’s threshold of a 1.5 dBA increase in ambient
noise levels with the project for environments with ambient noise levels in excess of 65 dBA
CNEL. However, noise levels in this vicinity from traffic on I-80 range from approximately 78
dBA to 82 dBA CNEL at a distance of 100 feet from the roadway centerline.7 It should be
noted that unlike linear units such as inches or pounds, decibels are measured on a
logarithmic scale and are thus added logarithmically. Thus combining noise levels of similar
noise sources having a difference in sound pressure levels of 10 or more decibels will not
result in any effective increase in the higher noise level. As the projected traffic noise levels
on Bridge Street even under summer 2025 Plus Project conditions would only reach 64.1
dBA CNEL, this is still more than 10 dBA below the I-80 traffic noise levels in this area. Thus,
the projected increase in traffic noise levels from traffic on Bridge Street of up to 55 dBA
CNEL would not result in any permanent increase in ambient noise levels at sensitive
receptors along this segment. Therefore, no off-site significant noise impacts would occur
from project-related traffic noise levels.
7 Truckee, Town of, 2006. Town of Truckee 2025 General Plan EIR, Appendix B. November 16.
NOVEMBER 2008 TRUCKEE RAILYARD DRAFT MASTER PLAN EIR
IV. SETTING, IMPACTS AND MITIGATION MEASURES
E. NOISE AND VIBRATION
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A significant impact would occur for proposed on-site noise sensitive land uses if the
cumulative (2025) traffic noise levels would exceed the Town’s normally acceptable
standards for new mixed-use development according to land use shown in Table IV.E-6.
Ambient noise levels greater than 65 dBA CNEL are in excess of the Town’s standards for
normally acceptable noise environments for new mixed-use residential development, such
as that proposed under the Railyard Master Plan.
The modeling results indicate that the summertime traffic noise levels for the year 2025
would not exceed 65 dBA CNEL along the modeled roadway segments of Donner Pass Road
which run adjacent to the Plan Area. The year 2025 summertime traffic noise levels along
these two roadway segments range from 62.1 to 63.1 dBA CNEL under without the project
conditions and from 63.2 to 63.3 dBA CNEL under with the project conditions. These noise
levels are within the Town’s “normally acceptable” range for new mixed-use residential
development. Therefore, no on-site significant exterior noise impacts would occur from
cumulative (2025) traffic noise levels.
c. Significant Noise Impacts. Significant noise impacts that would result from
implementation of the Master Plan are described below.
(1) Short-Term Impacts. Construction associated with build out of the Plan Area
would result in short-term noise impacts on adjacent land uses. The level and types of noise
impacts that would occur during construction are described below.
Impact NOI-1: Construction period activities could create significant short-term noise
impacts on existing noise sensitive land uses adjacent to the Plan Area, and on
buildings constructed within the Plan Area that would become occupied before full
buildout of the Plan Area. (S)
Noise levels from grading and other construction activities associated with build out of the
Truckee Railyard Master Plan may range up to 91 dBA Lmax at the closest off-site sensitive
receptors for very limited times when construction occurs near the project’s boundary. On-
site sensitive uses that may become occupied before complete build out of the Plan Area
could also experience noise levels from construction activities of up to 91 dBA Lmax when
located at a distance of 50 feet from an active construction area. Short-term noise impacts
would result from excavation, grading, and erecting of buildings within the Plan Area during
construction of proposed projects. Construction related short-term noise levels would be
higher than existing ambient noise levels in the Plan Area but would no longer occur once
construction is completed.
Two types of short-term noise impacts could occur during construction within the Plan Area.
First, construction crew commutes and the transport of construction equipment and
materials to construction sites within the Plan Area would incrementally increase noise
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levels on access roads leading to the sites. Although there would be a relatively high single-
event noise exposure potential causing intermittent noise nuisance (passing trucks at 50
feet would generate up to a maximum of 86 dBA Lmax), the effect on longer term (hourly or
daily) ambient noise levels would be small. Therefore, short-term construction related
impacts associated with worker commute and equipment transport to construction sites
within the Plan Area would be less than significant.
The second type of short-term noise impact is related to noise generated during excavation,
grading, and erection of buildings on
sites within the Plan Area.
Construction is completed in discrete
steps, each of which has its own mix
of equipment and, consequently, its
own noise characteristics. These
various sequential phases would
change the character of the noise
generated and, therefore, the noise
levels surrounding the site as
construction progresses. Despite the
variety in the type and size of
construction equipment, similarities in
the dominant noise sources and
patterns of operation allow
construction related noise ranges to
be categorized by work phase. Table
IV.E-13 lists typical construction
equipment noise levels recommended
for noise impact assessments, based
on a distance of 50 feet between the
equipment and a noise receptor. The
site preparation phase, which includes
excavation and grading of the site,
tends to generate the highest noise
levels, because the noisiest
construction equipment is
earthmoving equipment. Earthmoving
equipment includes excavating machinery such as backhoes, bulldozers, draglines, and
front loaders. Earthmoving and compacting equipment includes compactors, scrapers, and
graders. Typical operating cycles for these types of construction equipment may involve one
or two minutes of full-power operation followed by three or four minutes at lower power
settings.
Table IV.E-13 Typical Construction Equipment
Maximum Noise Levels
Type of
Equipment
Range of
Maximum
Sound Levels
(dBA at 50 ft.)
Suggested
Maximum
Sound Levels
for Analysis
(dBA at 50 ft.)
Pile Drivers 81 to 96 93
Rock Drills 83 to 99 96
Jackhammers 75 to 85 82
Pneumatic Tools 78 to 88 85
Pumps 68 to 80 77
Scrapers 83 to 91 87
Haul Trucks 83 to 94 88
Electric Saws 66 to 72 70
Portable Generators 71 to 87 80
Rollers 75 to 82 80
Dozers 85 to 90 88
Tractors 77 to 82 80
Front-End Loaders 86 to 90 88
Hydraulic Backhoe 81 to 90 86
Hydraulic
Excavators
81 to 90 86
Graders 79 to 89 85
Air Compressors 76 to 89 85
Trucks 81 to 87 85
Source: Bolt, Beranek & Newman, 1987. Noise Control for
Buildings and Manufacturing Plants.
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Construction of projects associated with buildout of the Plan is expected to require the use
of earthmovers such as bulldozers and scrapers, loaders and graders, water trucks and
other trucks. As shown in Table IV.E-10, the typical maximum noise level generated by
backhoes is assumed to be 86 dBA Lmax at 50 feet from the operating equipment. The
maximum noise level generated by bulldozers is approximately 88 dBA Lmax at 50 feet. The
maximum noise level generated by water and other trucks is approximately 85 dBA Lmax at
50 feet from these vehicles. Each doubling of the sound sources with equal strength would
increase the noise level by 3 dBA. Assuming each piece of construction equipment operates
at some distance apart from the other equipment, the worst-case combined noise level
during this phase of construction would be 91 dBA Lmax at a distance of 50 feet from an
active construction area.
The closest existing noise sensitive receptors would be the residential land uses located
along the north side of Donner Pass Road and Church Street bordering the western end of
the Plan Area. These residences would potentially be exposed to construction noise levels of
up to 91 dBA Lmax when construction associated with the roadway realignments would
occur. Other noise sensitive receptors would include residential land uses within the Plan
Area that would become occupied before full buildout of the Plan Area is complete. These
residences would potentially be exposed to construction noise levels of up to 91 dBA Lmax
when located at a distance of 50 feet from an active construction area. Residential land uses
south of the Plan Area along East River Street may experience construction noise levels of
up to 78 dBA Lmax when construction occurs along the Plan Area’s southern boundary.
Mitigation Measure NOI-1: In accordance with Town standards, the following multi-part
mitigation measure shall be implemented to reduce construction-related noise impacts
to a less-than-significant level. The Town shall condition approval of new development
within the Railyard Master Plan Area as follows:
NOI-1a: During all construction, the project sponsor shall comply with all of the
standard construction noise control measures of the Town’s General Plan Policy
P3.13, outlined as follows:
a. Equip all internal combustion engine driven equipment with intake and exhaust
mufflers that are in good condition and appropriate for the equipment;
b. Locate stationary noise generating equipment as far as possible from sensitive
receptors when sensitive receptors adjoin or are near a construction area;
c. Utilize “quiet” air compressors and other stationary equipment where
appropriate technology exists; and
d. The project sponsor shall designate a “disturbance coordinator” who shall be
responsible for responding to any local complaints about construction noise.
The disturbance coordinator will determine the cause of the noise complaint
(e.g., staring too early, bad muffler, etc.) and will require that reasonable
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measures warranted to correct the problem be implemented. The project
sponsor shall also post a telephone number for excessive noise complaints in
conspicuous locations in the vicinity of the construction Plan Area.
Additionally, the project sponsor shall send a notice to neighbors in the project
vicinity with information of the construction schedule and the telephone
number for noise complaints.
NOI-1b: The construction contractor shall ensure that all general construction
related activities are restricted to the hours of 7:00 a.m. to 9:00 p.m. on any day
except Sunday, or from 9:00 a.m. to 6:00 p.m. on Sunday.
Implementation of the above two measures would ensure construction-related
noise impacts are not significant. (LTS)
(2) Operational Period Impacts. Implementation of the Truckee Railyard Master
Plan would result in significant long-term noise impacts on existing noise sensitive land
uses in the vicinity and on proposed land uses within the Plan Area. The level and types of
operational noise impacts that would occur are described below.
It should be noted that unlike linear units such as inches or pounds, decibels are measured
on a logarithmic scale and are thus added logarithmically. Thus combining noise levels of
similar noise sources having a difference in sound pressure levels of 10 or more decibels
will not result in any effective increase in the higher noise level. It is for this reason that the
following analysis does not consider the combined traffic noise levels in the project vicinity
with the projected railroad noise levels since all of the modeled traffic noise levels on
roadways adjacent to the Plan Area are more than 10 decibels lower than the projected
railroad noise levels of 76 dBA CNEL.
Impact NOI-2: Implementation of the Truckee Railyard Master Plan could expose noise
sensitive land uses within the Railyard Master Plan Area to railroad-related noise levels
in excess of normally acceptable standards. (S)
As described in the existing noise environment discussion above, the proposed Plan Area is
located adjacent to the Union Pacific Railroad tracks which significantly affect the ambient
noise environment in the vicinity. Existing noise levels at a distance of 100 feet from the
railroad centerline are approximately 76 dBA CNEL. Environments with noise levels in excess
of 75 dBA CNEL are considered “unacceptable” for new residential development according to
the Town’s land use compatibility standards. Therefore, mitigation measures must be
implemented that would reduce railroad noise impacts to meet the Town’s exterior noise
level standard of 65 dBA CNEL for new mixed-use residential active use areas and the
interior noise level standard of 45 dBA CNEL.
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These railroad noise levels would attenuate to below 70 dBA CNEL at a distance of 200 feet
from the railroad centerline. This is within the Town’s “conditionally acceptable” range for
new mixed-use residential development and within the “normally acceptable” range for new
office, industrial, or commercial development. At a distance of 355 feet, railroad noise
levels would attenuate to below 65 dBA CNEL. This is within the Town’s “normally
acceptable” range for new mixed-use developments. In addition to distance attenuation, the
strategic placement of buildings to block the line of sight to the railroad line can further
reduce railroad noise levels by a minimum of 5 dBA. Therefore, for residential exterior
active use areas, such as backyards of single-family homes, that would be located between
200 and 355 feet of the railroad centerline, railroad noise levels could be reduced to meet
the Town’s standard of 65 dBA CNEL for such uses by strategically locating them so that the
line of sight to the railroad line is blocked by intervening buildings.
At 150 feet, railroad noise would attenuate to below 73 dBA CNEL. The Town considers
environments with ambient noise levels of 70 dBA to 75 dBA CNEL as “conditionally
acceptable” for new community park development. All proposed parks within the Plan Area
would be located beyond 150 feet from the railroad centerline. Therefore, all proposed
parks would be located within an ambient noise environment within the Town’s
“conditionally acceptable” range for new community park development.
In order to meet the Town’s interior noise level standards, noise reduction and insulation
features would need to be incorporated into the designs of residential buildings proposed
for development within the Plan Area. Again, these railroad noise levels would attenuate to
below 73 dBA CNEL at a distance of 150 feet from the railroad centerline, and to below 70
dBA CNEL at a distance of 200 feet from the railroad centerline. Based on the EPA’s
Protective Noise Levels (EPA 550/9-79-100, November 1978), with a combination of walls,
doors, and windows, standard construction for northern California residential buildings
would provide more than 25 dBA in exterior to interior noise reduction with windows closed
and 15 dBA or more with windows open. With windows open, proposed residences located
within 200 feet of the railroad centerline would not meet the Town’s interior noise standard
(i.e., 70 dBA – 15 dBA = 55 dBA). Therefore, any portions of residential units that would be
constructed within 200 feet of the railroad centerline would be required to incorporate
upgraded window and wall assemblies having a minimum sound transmission class rating
of STC-34. In addition, all residential units constructed within 355 feet of the railroad
centerline or anywhere in the Plan Area having a direct line of sight to the railroad shall
incorporate an alternative form of ventilation that would permit windows to remain closed
for a prolonged period of time. This would reduce railroad noise impacts to meet the
Town’s interior noise level standard for residential land uses of 45 dBA CNEL (i.e., 70 dBA –
25 dBA = 45 dBA).
Railroad-related noise impacts would also occur with single event noise occurrences such as
train horns sounding. While railroad related noise sources are exempt from the Town’s
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Municipal Code noise standards, sleep disturbance and annoyance due to train horns
sounding at the Bridge Street at-grade crossing could occur for residential land uses
proposed as part of the Master Plan. According to the Federal Transit Administration (FTA),
the reference sound level for locomotive horns is 107 SEL dBA (or 104 Lmax) at 100 feet from
at-grade crossings. At 200 feet from the railroad centerline this noise level would be
reduced to below 101 SEL dBA (or below 98 dBA Lmax). This would be below the general
exterior single event noise impact threshold of 105 SEL dBA (with windows closed) that
would result in sleep disturbance in a maximum of 10 percent of the population (i.e., when
the interior noise level exceeds 80 dBA). However, some sleep disturbance would still occur
for a small (less than 10) percent of the population. For new residential land uses that would
be located within 355 feet of the railroad track centerline and with a direct line of sight to
the railroad, incorporation of upgraded window and wall assemblies with a sound
transmission class (STC) of greater than STC-28 would help minimize such impacts.
In addition, noise sources with noticeable tonal content, such as train horns or high-pitched
sounds, may be perceived as more annoying than other sounds having the same noise level
in terms of dBA. Noise impact thresholds for such noise sources are typically accounted for
by lowering the established maximum or percentile exceedance standards by 5 dBA.
However, railroad-related noise impacts are exempt from the Town’s noise standards as
stated in Section 18.44.070 of the Municipal Code. Similar to the single event noise impact
discussion, a minimum setback requirement would reduce such impacts; however, some
level of annoyance would still occur. For new residential land uses that would be located
within 355 feet of the railroad track centerline and with a direct line of sight to the railroad,
incorporation of upgraded window and wall assemblies with a sound transmission class
(STC) of greater than STC-28 would help minimize such impacts.
In order to reduce railroad-related noise impacts to meet the Town’s exterior noise level
standard of 65 dBA CNEL and the interior noise level standard of 45 dBA CNEL for new
mixed-use residential developments and to minimize sleep disturbances due to single event
train noise impacts, the following mitigation measure shall be implemented:
Mitigation Measure NOI-2: To reduce railroad-related noise impacts on proposed noise
sensitive developments within the Plan Area. The following measures shall be
implemented:
a. All residential outdoor active use areas shall comply with a minimum 200-foot
setback from the centerline of the railroad main line; and any such uses that would
be located within 355 feet of the railroad centerline of the railroad main line shall,
to the extent feasible, be shielded from direct exposure to the railroad main line
by strategically locating them so that the line of sight to the railroad line is
blocked by intervening buildings to achieve an exterior noise level of 65dBA;
b. Any portions of residential units that would be constructed within 200 feet of the
railroad centerline shall incorporate upgraded window and wall assemblies with a
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minimum sound transmission class rating of STC-34. Quality control must be
exercised in construction to ensure all air-gaps and penetrations of the building
shell are controlled and sealed as required to meet an interior noise level of
45dBA;
c. All residential units constructed within 200 and 355 feet of the railroad centerline
or anywhere in the Plan Area having a direct line of sight to the railroad shall
incorporate an alternative form of ventilation to ensure that windows can remain
closed for a prolonged period of time;
d. All residential façades constructed within 355 feet of the railroad centerline with a
direct line of sight to the railroad shall incorporate upgraded window and wall
assemblies with a minimum sound transmission class of STC-30; and
e. All noise sensitive development projects within the Master Plan Area must submit
documentation to the Town’s Planners prior to issuance of building permits which
details the design features that would be incorporated into the project to reduce
train-related noise impacts.
Implementation of these mitigation measures would mitigate railroad noise levels to
comply with the Town’s General Plan exterior noise level standard of 65 dBA CNEL and
the interior noise level standard of 45 dBA CNEL for new mixed-use residential
developments. However, achievement of the mitigation measure for exterior outdoor
areas may not be feasible in all cases depending on final project design. It may be the
Town’s desire to have some outdoor area that exceeds the standard of 65 dBA. If that
occurs this impact would be significant unavoidable. Additionally, railroad-related
maximum and single-event noise level impacts and noise impacts resulting from the
noticeable tonal content of train horns would still occur. While these noise impacts are
short-term, sleep disturbance for a maximum of 10 percent of the population and
some level of annoyance would be expected to occur for new residential development
constructed within the Plan Area. As a result this impact would remain a significant
and unavoidable impact. (SU)
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