HomeMy WebLinkAboutReso 033-96 Noise Mitig FeeRESOLUTION NO. 33 - 96
A RESOLUTION OF THE CITY COUNCIL
OF THE CITY OF DUBLIN
ESTABLISHING AMOUNT OF NOISE MITIGATION FEE
FOR FUTURE DEVELOPMENTS WITHIN THE CITY OF DUBLIN
RECITALS
WHEREAS, the City Council of the City of Dublin has adopted Dublin Municipal Code
Chapter 5.112 creating and establishing the authority for imposing and charging a Noise
Mitigation Fee ("Fee") to mitigate the impacts caused by future development within the Eastern
Dublin Specific Plan and General Plan Amendment area; and
WHEREAS, the Eastern Dublin General Plan Amendment CGPA") and Specific Plan
CSP") were adopted by the City in 1993; and
WHEREAS, the GPA outlines future land uses for approximately 4176 acres within the
City's eastern sphere of influence including approximately 13,906 dwelling units and 9.737 million
square feet of commercial, office, and industrial development; and
WHEREAS, the SP provides more specific detailed goals, policies and action programs
for approximately 33 13 acres within the GPA area nearest to the City; and
WHEREAS, the GPA and SP areas ("Eastern Dublin") are shown on the Land Use Map
contained in the GPA (attached hereto as Exhibit A) and exclude the area shown on the Land Use
Map as "Future Study Area/Agriculture"; and
WHEREAS, a Program Environmental Impact Report ("EIR") was prepared for the GPA
and SP (SCH No. 91103604) and certified by the Council on May 10, 1993 by Resolution No.
51-93, and two Addenda dated May 4, 1993 and August 22, 1994 CAddenda") have been
prepared and considered by the Council; and
WHEREAS, the City Council adopted a "Mitigation Monitoring Program: Eastern Dublin
Specific Plan/General Plan Amendment" by Resolution No. 53-93 which includes mitigation
measures to assure that development within Eastern Dublin pays its proportionate share to
mitigate impacts caused by development within Eastern Dublin; and
WHEREAS, the GPA, SP, EIR and Addenda describe the impacts of contemplated future
development on existing residences in Eastern Dublin through the year 2025, and contain an
analysis of the need for mitigation measures required to mitigate such impacts; and
WHEREAS, a detailed comprehensive study of the impacts of contemplated future
development on existing residences in Eastern Dublin from future roadway noise, along with an
analysis of the needed improvements to mitigate such noise was prepared by Charles M. Salter
Associates, Inc., dated February 20, 1996, entitled "Eastern Dublin Noise Mitigation Fee Study';
(Exhibit B hereto, referred to herein as the "study"); and
WHEREAS, the study sets forth the relationship between contemplated future
development, the needed mitigation measures, and the estimated costs of those measures; and
WH2EREAS the study was available for public inspection and review for ten (10) days
prior to this public hearing; and
WHEREAS, the Agenda Statement describes the administrative costs which will be
incurred by the City in implementing the Noise Mitigation Fee.
FINDINGS
WHEREAS, the City Council finds as follows:
A. The purpose of the Noise Mitigation Fee (hereafter "Fee" ) is to finance the
mitigation measures identified in the study. Such mitigation measures are specifically described in
the study. The mitigation measures described in the study are hereinaf~er referred to as the
"Improvements."
B. The Fees collected pursuant to this resolution shall be used to finance the
Improvements to the residences shown (with costs) in Table 1 of the study and other noise
attenuation measures specified herein.
C. ARer considering the study, the testimony received at this noticed public hearing,
the Agenda Statement, the General Plan, the GP& the SP, the EIK and Addenda, the Mitigation
Monitoring Program and all correspondence received (hereafter "record") the Council approves
and adopts said study, and incorporates such herein, and further finds that the future development
in Eastern Dublin will generate the need for the Improvements and the Improvements are
consistent with the City's General Plan, the GPA and the Eastern Dublin Specific Plan.
D. The adoption of the proposed fee is not a project subject to CEQA because the
whole of the action does not have a potential for resulting in a physical change in the environment,
directly or ultimately. The provisions of funds to mitigate cumulative noise impacts to existing
residences in the Eastern Dublin Specific Plan and General Plan Amendment area will not have a
potential for resulting in a physical change to the environment, directly or ultimately.
E. In adopting the Fee, the Council is exercising its powers under Article XI § 7 of
the California Constitution.
F. The record establishes:
1. That there is a reasonable relationship between the need for the
Improvements and the impacts of the types of development for which the corresponding fee is
charged in that new development in Eastern Dublin -- both residential and non-residential -- will
generate persons who live, work and/or shop in Eastern Dublin and who generate or contribute to
the need for the Improvements; and
2. That there is a reasonable relationship between the Fee's use (to pay for the
construction of the Improvements and administration of the Fee program) and the type of
~levelopment for which the Fee is charged in that all development in Eastern Dublin -- both
residential and non-residential -- generates or contributes to the need for the Improvements; and
3. That there is a reasonable relationship between the amount of the Fee and
the cost of the Improvements or portion thereof attributable to development in Eastern Dublin in
that the Fee is calculated based on the number of vehicle trips generated per day by specific types
of land uses, the total amount it will cost to construct the Improvements and to administer the Fee
program, fee per trip, and the fee per trip multiplied by the number of trips per day each use
generates to arrive at the respective fee per residential unit or thousand square feet or portion
thereof of non-residential use; and
4. That the cost estimates set forth in the study are reasonable cost estimates
for constructing the Improvements and administering the Fee program, and the Fees expected to
be generated by future development will not exceed the projected costs of constructing the
Improvements and administrative costs; and
5. The method of allocation of the Fee to a particular development bears a fair
and reasonable relationship to each development's burden on, and benefit from, the Improvements
to be funded by the Fee, in that the Fee is calculated based on the number of vehicle trips each
particular development will generate.
G. The study is a detailed analysis of how existing residences will be affected by noise
generated by new development in Eastern Dublin.
ADOPTION OF FEE
NOW THEREFORE, the City Council of the City of Dublin does RESOLVE as follows:
1. Definitions
a. "Campus Office" shall mean any development constructed or to be
constructed on land having a General Plan or SP land use designation of Campus Office, as that
term is defined in the GPA.
b. "Development" shall mean the construction, alteration or addition of any
building or structure within the City of Dublin and within Eastern Dublin.
c. "Eastem Dublin" shall mean all property within the "General Plan
Amendment Study Area" as shown on the Land Use Map (Exhibit A hereto) excepting the
property designated as "Future Study Area/Agriculture."
d. "General Commercial" shall mean any development constructed or to be
constructed on land having a General Plan or SP and use designation of General Commercial, as
that term is defined in ~he GPA.
e. "High Density Dwelling Unit" shall mean a dwelling unit as defined in the
Uniform Building Code CuBC) as adopted by the City of Dublin constructed or to be constructed
on property designated by the SP and GPA for 25.1 or more units per acre.
f. "Improvements" shall include those improvements described in the Study.
"Improvements" shall also include comparable alternative improvements should later changes in
technologies make alternative improvements feasible.
g. "Industrial Park" shall mean any development constructed or to be
constructed on land having a General Plan or SP land use designation of industrial Park, as that
term is defined in the GPA.
h. "Low Density Dwelling Unit" shall mean a dwelling unit as defined in the
Uniform Building Code (UBC) as adopted by the city of Dublin constructed or to be constructed
on property designated by the SP and GPA for up to 6.0 units per acre.
i. "Medium Density Dwelling Unit" shall mean a dwelling unit as defined in
the Uniform Building Code (UBC) as adopted by the City of Dublin constructed or to be
constructed on property designated by the SP and GPA for 6.1 to 14.0 units per acre.
j. "Medium/High Density Dwelling Unit" shall mean a dwelling unit as
defined in the Uniform Building Code (UBC) as adopted by the City of Dublin constructed or to
be constructed on property designated by the SP and GPA for 14.1 to 25.0 units per acre.
k. "Neighborhood Commercial" shall mean any development constructed or
to be constructed on land having a General Plan or SP land use designation of Neighborhood
Commercial, as defined in the GPA.
2. Noise Mitigation Fee Imposed.
a. A Noise Mitigation Fee ("Fee") shall be charged and paid for each Low
Density, Medium Density, Medium/High Density and High Density Dwelling Unit within Eastern
Dublin no later than the date of final inspection for the unit.
b. A Fee shall be charged and paid for each 1000 square feet or portion
thereof of non-residential buildings or structures, excluding parks and public/semi-public uses,
within Eastern Dublin by the date that the building permit is issued for construction of such
building or structure.
3. Amount of Fee.
The amount of the Fee shall be as set forth on Exhibit C attached hereto and
incorporated herein.
4. Exemptions From Fee.
a,
The Fee shall not be imposed on any of the following:
(1) Any alteration or addition to a residential structure, except to the
extent that a residential unit is added to a single family residential
unit or another unit is added to an existing multi-family residential
unit;
(2) Any replacement or reconstruction of an existing residential
structure that has been destroyed or demolished provided that the
4
(3)
building permit for reconstruction is obtained within one year after
the building was destroyed or demolished unless the replacement
or reconstruction increases the square footage of the structure
fifty percent or more.
Any replacement or reconstruction of an existing non-residential
structure that has been destroyed or demolished provided that the
building permit for new reconstruction is obtained within one year
after the building was destroyed or demolished.
5. Use of Fee Revenues:
a. The revenues raised by payment of the Fee shall be placed in the Capital
Project Fund. Separate and special accounts within the Capital Project Fund shall be used to
account for such revenues, along with any interest earnings on each account. The revenues (and
interest) shall be used for the following purposes:
(1) To reimburse property owners of the residences identified in the
study for construction of the improvements described in the study
in an amount not to exceed shown on the Table 1 of the study,
provided that the property owner has entered into an agreement
with the City regarding the improvements to be made, their cost
and the means of payment/reimbursement prior to construction of
any improvements;
(2) To fund other noise attenuation or mitigation measures within the
GPA and SP areas, whether public or private, which the City
Council finds will reduce cumulative noise impacts resulting from
new development in the GPA and SP areas, provided that the
Council also finds that sufficient revenues remain or will be
collected to reimburse property owners pursuant to subparagraph
(1) above; and
(3) To pay for and/or reimburse costs of program development and
ongoing administration of the Fee program.
b. Fees in these accounts shall be expended only for the Improvements and
only for the purpose for which the Fee was collected.
6. Standards.
The standards upon which the needs for the Improvements are based are the
standards of the City of Dublin, including the standards contained in the General Plan, the GPA,
SP, EI2R, and Addenda.
7. Periodic Review.
During each fiscal year, the City Manager shall prepare a report for the City
Council identifying the balance of Fees in each account.
8. Administrative Guidelines.
The Council may, by resolution, adopt administrative guidelines to provide
procedures for calculation of the Fee, the timing of and procedures for reimbursement to property
owners for construction of the Improvements and other administrative aspects of the Fee.
9. Subsequent Analysis of the Fee.
The Fee established herein is adopted and implemented by the Council in reliance
on the record identified above. Periodically, the City may conduct further study and analysis to
determine whether the Fee should be revised.
10. Effective Date.
This resolution shall become effective immediately. The Fee provided in Sections
2 and 3 of this resolution shall be effective 60 days from the effective date of the resolution.
11. Severability.
Each component of the Fee and all portions of this resolution are severable.
Should any individual component of the Fee or other provision of this resolution be adjudged to
be invalid and unenforceable, the remaining component or provisions shall be and continue to be
fully effective, and the Fee shall be fully effective except as to that component that has been
judged to be invalid.
vote:
PASSED, APPROVED AND ADOPTED this 261h day of March, 1996, by the following
AYES: Councilmembers Barnes, Burton, Howard, Moffatt and Mayor Houston
NOES: None
ABSENT: None
ABSTAIN: None
ATTEST: CiT~~:
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~General Plan
-Eastern Extended Planning Area
LAND USE MAP
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t t Wi~ convert To Futt~e Sludy Area/Agrlcd~e where daletrained Inconsistent wfih APA (see lexl for complete discussion
[XltiltlTA
EASTERN DUBLIN
NOISE MITIGATION FEE STUDY
CSA Project No. 96-010
Prepared for:
Dennis H. Carrin~on, AICP
Senior Planner
City of Dublin
P.O. Box 2340
Dublin, CA 94568
Frepared by:
Eric L- Broadhurst, PE
Senior Consultant
20 February 1996
EXHIBIT
'TD
INTRODUCTION
In compliance with the Eastern Dublin General Plan Amendment and Specific Plan EIR, the City
of Dublin intends, by resolution, to set forth a Noise Mitigation Fee amount. The Noise
Mitigation Fee will mitigate impacts identified in Impact 3. 1 0/B of the EIR. The fee amount will
be adopted pursuant to Ordinance 1-95, which established the Noise Mitigation Fee. The City
intends that the Noise Mitigation Fee be used to mitigate the cumulative impacts of exposure of
existing residences to future roadway noise.
BACKGROUND
The Eastern Dublin General Plan Amendment and Specific Plan Environmental Impact Report
(EIR) assessed the project's potential noise impacts. The project would contribute cumulative
traffic-related noise impacts in the region. Impact 3.10/B, "Exposure of Existing Residences to
Future Roadway Noise," addressed the cumulative traffic-related noise impacts on existing
residences along Fallon Road and Tassajara Road. It determined the cumulative noise impact of
the Project to be significant.
Mitigation Measure 3.10/7.0 would, if properly implemented, reduce cumulative noise impacts to
a potentially significant level. Mitigation Measure 3.10/7.0 reads as follows:
MM 3.10/7.0
In order to mitigate this significant cumulative impact, the City should develop a noise
mitigation fee to pay for the mitigating measures such as noise barriers, earthen berms, or
retrofitting existing structure with sound-rated windows. The mitigation fee could be
developed on a "dollars for decibels" basis. For example, if the future noise level is predicted
Page '2 ,..
to increase by 4 dB, and the Project will contribute 2 dB, then the applicant should be
responsible for 50 percent of the total cost of any off-site mitigation measures.
This mitigation measure is designed especially to reduce cumulative impacts related to noise.
This is an experimental concept which has been adopted by other jurisdictions in the Tri-Valley.
The section of the EIR addressing Impact 3.10/B reads as follows:
Noise
IM 3.10/B Exposure of Existing Residences to Future Roadway Noise
The project would contribute to cumulative traffic-related noise impacts in the region. Each
cumulative project may contribute one or two decibels to the overall noise level in the
subregional area. This may typically be considered no impact since the increase is generally
less than 3 dB. However, over the long term, the noise level increases in a substantial
manner. This would be hue along such roadways as Fallon and Tassajara Roads. Therefore,
the noise impact of the Project is considered a significant cumulative impact.
SUMMARY
This report summarizes the results of the traffic noise mitigation analysis for existing residences
in the Eastern Dublin Specific Plan area as required in the scope of work for this study. The
Specific Plan will provide for the establishment of Single Family, Medium Density, Medium-
High Density, and High Density residential uses, and General Commercial, Neighborhood
Commercial, Campus Office, and Industrial Park uses in the study area. To improve access to
these developments, Tassajara Road will be widened and Fallon Road will be both widened and
rerouted to intersect with Tassajara Road near the county line.
.,: ..- Page 3
A survey was conducted of the existing homes within the study area along Fallon and Tassajara
Roads. Thirteen homes were identified as being potentially impacted: twelve along Tassajara
Road and one along Fallon Road. Of the thirteen homes, two were identified as being on
property that would be crossed by the proposed Fallon Road reroute: 6815 and 6833 Tassajara
Road, and therefore eliminated.
Both indoor and outdoor acoustical measurements were conducted in the study area. A computer
analysis was then performed of the existing and build-out noise levels to determine the
appropriate amount of noise reduction necessary. Construction of noise barriers, exterior facade
modifications, and ventilation modifications were considered for specific residences. The total
cost of the proposed mitigation was determined. A methodology was then proposed for
assigning mitigation costs to the various projects in the area based on the number of trips per day
they generate.
MITIGATION/COSTS SUMMARY
· Six homes will need fences constructed around their outdoor use space.
· One home will need a ventilation system added at certain second floor rooms.
· It is estimated that the mitigation costs per impacted residence will range from $11,000 to
$27,500.
Distribution of the noise mitigation costs among the various developers is proposed to be done
on the basis of the number of trips per day generated by each type of residential and non-
residential use.
Page
Since some of the homes in the stud)' may be removed as part of the new development,
mitigation should not be implemented until the traffic volumes on Tassajara Road increase to
2,000 p.m. trips per day.
CRITERIA
This study has noise criteria for both the indoors of residences and their outdoor use spaces. If
the predicted future outdoor noise level exceeds DNL~ 60 dB, then noise mitigation must be
considered. The goal of the mitigation is an outdoor DNL of 60 dB and an indoor DNL 45 dB.
EXISTING AND FUTURE NOISE ENVIRONMENT
The major existing noise source in the study area is vehicular traffic along Tassaj ara Road.
Between 25 and 26 January 1996, we conducted a 24-hour noise measurement along Tassajara
Road; we also conducted 1 O-minute indoor and outdoor noise measurements at 6960 Tassajara
Road, and outdoor noise measurements at 6237 Tassajara Road. The purpose of the 24-hour
measurement was to determine the existing noise level in the area; the purpose of the 10-minute
measurements was to calculate the amount of outdoor-to-indoor noise reduction provided by the
buildings, and calibrate our computer noise model.
We measured a DNL of 71 dB at a distance of 25 feet from the roadway centerline. We also
calculated that the building shell provided 20 dB of noise reduction with the windows closed,
which is typical for a building of this type.
Readers not familiar with the fundamental concepts of environmental acoustics are referred to
Appendix A.
.,. ." Page 5
Existing and future traffic noise levels for Tassajara and Fallon Roads were calculated using a
computer program called SOUND32.2 Traffic volumes, speeds, and estimated truck
percentages used in the model were based on information supplied by the City, and are
summarized in Appendix B. The data is for "Cumulative Build-out with Project." 3 Table 1
summarizes the existing and future noise levels at the residences in the study. The existing
residences are located at distances from the roadway centerlines of 75 to 800 feet.
ANALYSIS/RECOMMENDATIONS
In general, barriers were used to reduce outdoor noise and first floor indoor noise to the project
criteria; at second floors, where the barriers would not have an appreciable effect, window and/or
ventilation modifications are recommended.
Exterior
In order to meet the project outdoor noise criterion of 60 dB DNL, it will be necessary to
construct barriers around the outdoor use spaces of six homes. Table 1 summarizes the height
requirements. The barrier may be an earthen berm, fence, or a combination of the two.
For a fence to act as a noise barrier, it will need to be solid from top to bottom, have no cracks or
gaps in its face, and have a surface density equal to or greater than that of 1-1/2 inch thick fence
boards (e.g., 2x8 redwood). To avoid gaps in the face of wood fences, overlapping slats or a
tongue-and-groove material should be used.
2 SOUND32 is a version of the Federal Highway Administration's Traffic Noise Prediction Model
(FHWA RD--77--108) that incorporates the Califomia Vehicle Noise emission levels (CALVENO)
curves.
3 "Cumulative Build-out with Project" is one of the transportation scenarios evaluated in the Expected
Land-Use section of the Tri-Valley Model, This scenario includes full build-out of all approved
development and all land uses included in adopted City General Plans.
0
=-
TABLE 1:
Summary of Noise Levels and Mitigation Costs
Tass~ara DNL, in dB Barrier
Address ExistingI Future Length, in
5020 46 54 ~-
5374 52 60 --
5378 52 60 --
5868 61 69 180
6060 61 69 180
6237 63 71 180
6407 50 58 --
6582 56 64 160
6960 (Floor 2) 54 64 --
6960 (deck) 51 60 --
7020 56 65 180
4233 Fallon 49 65 140
Barrier Cost of Barrier
Height, in ftBarrier Design
-- $o $o $o
-- $o $o $o
-- $o $o $o
12 $23,000 $4,500 $0
i2 $23,000 $4,500 $0
12 $23,000 $4,500 $0
-- $0 $0 $0
9 $20,000 $4,500 $0
-- $o $o $11,ooo
-- $o $o $o
7 $19,000 $4,500 $0
7 $16,000 $4,5oo $0
TOTAL
Note: All barriers are for outdoor use spaces in the fronts of the homes.
Cost of [~ Total
Ventilation Cost
$o
$o
$o
$27,500
$27,500
$27,500
$o
$24,500
$11,000
$0
$23,500
$20,500
$162,000
)(.
X
X
X
X
OUTDOOR
X
USE
SPACE x
X
X
X
X X )( X
PROPOSED
FENCE
X
X
X
X
ROADWAY
TYPICAL
FIGURE
PROPOSED
FENCE
LAYOUT
130 Suttef Street San Francisco Calilornia 94104 Tel: 415 397 0,:"42 Fax: 415 397 045,4
Page
Interior
Residences typically reduce noise from outdoors to indoors by 15 dB with the windows open.
Since the noise barriers are reducing the outdoor DNL to 60 dB or less, the first floor rooms will
not need any mitigation to meet the indoor noise criterion of DNL 45 dB. However, the barriers
do not have an appreciable effect on the noise level at the second floor elevation. Therefore, for
residences where a sound barrier is necessary, second floor windows having a view of Tassajara
Road will need to be closed to meet 45 dB DNL. This includes 6960 Tassajara Road. For this
home, second floor rooms facing the roadway should be provided with a mechanical ventilation
system.
Implementation
We understand that some of the homes surveyed as part of the study may be removed as part of
the new development in the area. Significant traffic noise increases will likely take several years
to occur; at that time, some homes identified as being affected may have already been removed
for new development. Therefore, you may want to delay implementing the mitigation until there
is a noticeable increase in traffic noise. A practical way to determine this is through a
combination of noise and traffic volume measurements. The mitigation should be implemented
when the traffic volumes on Tassajara Road increase to 2,000 p.m. trips per day.
COST ESTIMATE
Saarman Construction has reviewed the proposed mitigation for the project to estimate the
associated construction costs. Their estimates for the noise barriers and ventilation systems are
Page 7
summarized in Table 1. The barrier lengths are estimated as shown in Figure 1 for a typical
home. The ventilation system costs are for three 150 square foot rooms facing the roadway.
In addition to the costs associated with construction are design costs necessary for site plans,
architectural drawings, and structural calculations for the fences. Richard Avelar & Associates'
estimate of the design cost is shown in Table 1. The estimates assume that each home's design
work would be done individually.
NOISE MITIGATION FEE
In order to allocate the noise mitigation costs equitably among the various developments, a
"dollars for decibels" system should be used. Since increases in noise are directly related to
increases in traffic volume, the following procedure should be used:
1. Multiply the number of residential units or 1,000's of square feet of non-
residential land uses by their Institute of Traffic Engineers (ITE) trip generation factor to
determine the total number of trips per day each type of use will contribute to the total number of
trips per day in the Eastern Dublin General Plan at buildout.
2. Sum the total number of trips per day each type of use will contribute to arrive at
the total number of trips per day in the Eastern Dublin General Plan at buildout.
3. Divide the costs of mitigating noise impacts to existing residences in the Eastern
Dublin Specific Plan and of administering the fee to anive at the fee for each automobile trip
generated.
4. Multiply the fee per trip generated times the number of trips each residential or
non-residential land use unit generates to arrive at its respective fee per residential unit or 1000
square feet of non-residential uses.
ELB/mac
APPENDIX A
FUNDAMENTAL CONCEPTS OF ENWIRONMENTAL NOISE
This section provides background information to aid in understanding the technical aspects of
this report.
Three dimensions of environmental noise are important in determining subjective response.
These are:
a)
b)
C)
The intensity or level of the sound;
The frequency spectrum of the sound; and
The time-varying character of the sound.
Airborne sound is a rapid fluctuation of air pressure above and below atmospheric pressure.
Sound levels are usually measured and expressed in decibels (dB), with 0 dB corresponding
roughly to the threshold of hearing.
The "frequency" of a sound refers to the number of complete pressure fluctuations per second in
the sound. The unit of measurement is the cycle per second (cps) or hertz (Hz). Most of the
sounds which we hear in the environment do not consist of a single frequency, but of a broad
band of frequencies, differing in level. The name of the frequency and level content of a sound is
its sound spectrum. A sound spectrum for engineering purposes is typically described in terms
of octave bands which separate the audible frequency range (for human beings, from about 20 to
20,000 Hz) into ten segments.
Many rating methods have been devised to permit comparisons of sounds having quite different
spectra. Surprisingly, the simplest method correlates with human response practically as well as
the more complex methods. This method consists of evaluating all of the frequencies of a sound
in accordance with a weighting that progressively de-emphasizes the importance of frequency
components below 1000 Hz and above 5000 Hz. This frequency weighling reflects the fact that
human hearing is less sensitive at low frequencies and at extreme high frequencies relative to the
mid-range.
The weighting system described above is called "A"-weighting, and the level so measured is
called the "A-weighted sound level" or "A-weighted noise level." The unit of A-weighted sound
level is sometimes abbreviated "dBA." In practice, the sound level is conveniently measured
using a sound level meter that includes an electrical filter corresponding to the A-weighting
characteristic. All U.S. and international standard sound level meters include such a filter.
Typical sound levels found in the environment and in industry are shown in Figure A-1.
..., ,-, Page 2
Although a single sound level value may adequately describe environmental noise at any instant
in time, community noise levels vary continuously. Most environmental noise is a
conglomeration of distant noise sources which results in a relatively steady background noise
having no identifiable source. These distant sources may include traffic, wind in trees, industrial
activities, etc. and are relatively constant from moment to moment. As natural forces change or
as human activity follows its daily cycle, the sound level may vary slowly from hour to hour.
Superimposed on this slowly varying background is a succession of identifiable noisy events of
brief duration. These may include nearby activities such as single vehicle passbys, aircraft
flyovers, etc. which cause the environmental noise level to vary from instant to instant.
To describe the time-varying character of environmental noise, statistical noise descriptors were
developed. "L10" is the A-weighted sound level equaled or exceeded during 10 percent of a
stated time period. The L10 is considered a good measure of the maximum sound levels caused
by discrete noise events. "L50" is the A-weighted sound level that is equaled or exceeded 50
percent of a stated time period; it represents the median sound level. The "Lg0" is the A-
weighted sound level equaled or exceeded during 90 percent of a stated time period and is used
to describe the background noise.
As it is often cumbersome to quantify the noise environment with a set of statistical descriptors, a
single number called the average sound level or "Leq" is now widely used. The term "Leq"
originated from the concept of a so-called equivalent sound level which contains the same
acoustical energy as a varying sound level during the same time period. In simple but accurate
tectmical language, the Leq is the average A-weighted sound level in a stated time period. The
Leq is particularly useful in describing the subjective change in an environment where the source
of noise remains the same but there is change in the level of activity. Widening roads and/or
increasing traffic are examples of this kind of situation.
In determining the daily measure of environmental noise, it is important to account for the
different response of people to daytime and nighttime noise. During the nighttime, exterior
background noise levels are generally lower than in the daytime; however, most household noise
also decreases at night, thus exterior noise intrusions again become noticeable. Further, most
people trying to sleep at night are more sensitive to noise.
To account for human sensitivity to nighttime noise levels, a special descriptor was developed.
The descriptor is called the DNL (Day/Night Average Sound Level) which represents the 24-
hour average sound level with a penalty for noise occurring at night.
The DNL computation divides the 24-hour day into two periods: daytime (7:00 am to 10:00
pro); and nighttime (10:00 pm to 7:00 am). The nighttime sound levels are assigned a 10 dB
penalty prior to averaging with daytime hourly sound levels. For highway noise environments,
the average noise level during the peak hour traffic volume is approximately equal to the DNL.
Page
The effects of noise on people can be listed in three general categories:
a)
b)
c)
Subjective effects of annoyance, nuisance, dissatisfaction;
interference with activities such as speech, sleep, and learning; and
Physiological effects such as startle, hearing loss.
The sound levels associated with environmental noise usually produce effects only in the first
two categories. Unfortunately, there has never been a completely predictable measure for the
subjective effects of noise nor of the corresponding reactions of annoyance and dissatisfaction.
This is primarily because of the wide variation in individual thresholds of armoyance and
habituation to noise over time.
Thus, an important factor in assessing a person's subjective reaction is to compare the new noise
environment to the existing noise environment. In general, the more a new noise exceeds the
existing, the less acceptable the new noise will be judged.
With regard to increases in noise level, knowledge of the following relationships will be helpful
in understanding the quantitative sections of this report: '
a)
Except in carefully controlled laboratory experiments, a change of only 1 dB in sound level
cannot be perceived.
b) Outside of the laboratory, a 3 dB change is considered a just-noticeable difference.
c)
A change in level of at least 5 dB is required before any noticeable change in community
response would be expected.
d)
A 10 dB change is subjectively heard as approximately a doubling in loudness, and would
almost certainly cause an adverse community response.
SF
MUNI
A-WEIGHTED
SOUND PRESSURE
IN DECIBELS
140
CIVIL
DEFENSE SIREN (100')
JET TAKEOFF (200')
RIVETING MACHINE
130
120
110
.)
DIESEL BUS (15')
100
BAY AREA RAPID TRANSIT
TRAIN PASSBY (10')
OFF HIGHWAY VEHICLE (50')
PNEUMATIC DRILL (50')
LIGHT-RAIL VEHICLE (,35')
FREIGHT CARS (100')
VACUUM CLEANER (10')
SPEECH (1')
AUTO TRAFFIC NEAR FREEWAY
LARGE TRANSFORMER (200')
AVERAGE RESIDENCE
90
80
70
60
50
40
SOFT WHISPER (5')
RUSTLING
THRESHOLD OF
LEAVES
HEARING
3O
2O
10
LEVEL,
THRESHOLD OF PAIN
ROCK MUSIC BAND
PILEDRIVER (50')
AMBULANCE SIREN
Ooo')
BOILER ROOM
PRINTING PRESS PLANT
GARBAGE DISPOSAL IN THE HOME
INSIDE SPORTS CAR, 50 MPH
DATA PROCESSING CENTER
DEPARTMENT, STORE
PRIVATE BUSINESS OFFICE
LIGHT TRAFFIC (100')
TYPICAL MINIMUM NIGHTTIME
LEVELS--RESIDENTIAL AREAS
RECORDING STUDIO
MOSQUITO .(3')
(100') = DISTANCE IN FEET
BETWEEN SOURCE
AND LISTENER
TYPICAL
· JEASURED IN
AND
Charles
SOUND LEVELS
THE ENVIRONMENT
INDUSTRY
S 0 C i a t e s I n c 13o suller Slree~ San Francisco
FIGURE A-1
1107 C
Cahforma 94104 '[el: 415 397 0,442 Fax: 415 397 045.~
APPENDIX B
The following table lists the traffic information used in the determination of existing and future DNL:
Tassajara Road, North of Gleason Road
Scenario
Existing (Year 1995)
Cumulative Build-out with Project 1 (2010)
Peak Hour
Volume Speed Truck %
503 50 2
3,196 p.m. 45 4
Future Failon Road Extension
Scenario
Cumulative Build-out with Project (2010)
Peak Hour
Volume
1,984 a.m.
Speed Truck %
35 2
"Cumulative Build-out with Project" is one of the transportation scenarios evaluated in the Expected Land-Use section of the
Tri-Valley Model. This scenario includes full build-out of all approved development and all land uses included in adopted
City General Plans.
Sheet1
NOISE MITIGATION FEE
EASTERN DUBLIN GENERAL PLAN
CIRCULATION FOR CHARGEABLE LAND USES
RESIDENTIAL UNITS
Low Density .01-6.0 unit/ac.
Medium Density 6.1-14.0 univac.
Medium High Density 14.1-25.0 unit/ac.
High Density 25.1 + unit/ac.
SUBTOTAL
NON-RESIDENTIAL
t
Ger,'-'-al Commercial
Neighborhood Commercial
Campus Office
Industrial Park
SUBTOTAL
TOTAL
GRAND TOTAL
g: PA96007\FEEC HT1
TRIPS PER DAY
PER UNIT
3,916
4,863
2,680
2,447
13,906
SQ. FEET TRIPS PER DAY
PER 1000 sq.ft.
3,435,000 50
980,000 50
3,952,000 15
1,370,000 5
9,737,000
DAILY
TRIPS
10 39,160
10 48,630
7 18,760
6 14,682
121,232
DAILY
TRIPS
171,750
49,000
59,280
6,850
286,880
408,112
FEE PER FEE PER FEE BY
TRIP UNIT USE TYPE
0.474233
0.474233
0.474233
0.474233
$4.74 $18,570.94
$4.74 $23,061.93
$3.32 $8,896.60
$2.85 $6,962.68'
$57,492.15
FEE PER FEE PER
TRIP 1000sq.~.
0.474233 $23.71
0.474233 $23.71
0.474233 $7.11
0.474233 $2.37
$81,449.43
$23,237.39
$28,112.50
$3,248.49
$136,047.82
$193,539.97
$193,539.97'
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EXHIBIT c