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ACKNOWLEDGEMENTS
The Traffic Noise Analysis Protocol embodies the collective ideas and comments
of many individuals without whom we would not have been able to successfully
complete this Project.
A multi- District and HQ Continuous Improvement Team developed key
concepts of the Protocol. These included a definition of substantial noise
increase, the Federal and State noise analysis process, and the development of
noise abatement cost effectiveness and reasonableness factors. One of the key
results is a truly innovative and objective approach to arriving at a noise
abatement decision. We wish to take this opportunity to thank and
acknowledge Brian Smith, Environmental Program Manager, for empowering
us to make decisions, and our fellow members, mentor, and team facilitator:
· Victor Zeuzem – District 4 Environmental Engineering, Team Member
· Jamal El- Jamal and Ralph Thunstrom – District 7 Environmental
Engineering, Team Member and Proxy, respectively.
· Japtej Gill – District 10 Environmental Engineering, Team Member
· Richard Grob – District 11 Environmental Engineering, Team Member
· Mary Beth Herritt – HQ Design and Local Programs, Team Member
· Bob Giess – HQ Environmental Program, Team Mentor
· Ed Imai - HQ Environmental Program, Team Facilitator
· Joya Gilster – HQ Environmental Program, Assistant to the Team and
Preparer of Management Presentation.
In addition to the above named individuals, we wish to extend our gratitude to
our partners in FHWA for their constructive review and comments on the
Protocol. In particular we want to thank:
· Joan Bollman, FHWA, California Division
· Jeff Lewis, FHWA, California Division
· Merrill Deskins, FHWA, Region 9
· Bob Armstrong, FHWA, Washington, D. C.
· Steve Ronning, FHWA, Washington, D. C.
To all the above named persons and all others that contributed to this Protocol
we want to sincerely thank you for your support!
Keith Jones – HQ Environmental Program, Author, Team Leader
Rudy Hendriks – HQ Environmental Program, Author, Team Member
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INTRODUCTION
The Traffic Noise Analysis Protocol ( hereafter referred to as the Protocol)
contains Caltrans noise policies, which fulfill the highway noise analysis and
abatement/ mitigation requirements stemming from the following State and
Federal environmental statutes:
· California Environmental Quality Act ( CEQA)
· National Environmental Policy Act ( NEPA)
· Title 23 United States Code of Federal Regulations, Part 772 “ Procedures for
Abatement of Highway Traffic Noise and Construction Noise” ( 23 CFR 772)
· Section 216 et seq. of the California Streets and Highways Code.
Policies, procedures and practices are provided in this Protocol for use by
agencies that sponsor new construction or reconstruction transportation projects.
The Protocol is designed to evaluate the potential traffic and construction
generated noise impacts, and determines reasonable and feasible noise
abatement/ mitigation for the project.
Special terms used in this Protocol have been defined for implementation
purposes and can be found in Section 7, Glossary.
Future versions of the Protocol will be issued, as necessary, to incorporate
changes in the laws, regulations, policy, procedures, and practices pertaining
to traffic and construction generated noise requirements and analysis.
The Technical Noise Supplement ( hereafter referred to as TeNS) is a
supplement to the Protocol, and contains Caltrans noise analysis procedures,
practices, and other useful technical noise background information.
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1. AFFECTED PROJECTS, REQUIREMENTS, AND ANALYSES
1.1 Affected Projects
Transportation projects affected by this Protocol are Type I projects. A Type I
project is defined in 23 CFR 772 as follows. A proposed Federal or Federal- aid
highway project for the construction of a highway on a new location, or the
physical alteration of an existing highway which significantly changes either the
horizontal or vertical alignment, or increase the number of through- traffic lanes.
Section 2.1 extends this definition to State- funded highway projects and adds
the FHWA interpretation of the above definition.
1.2 Federal Requirements
1.2.1 National Environmental Policy Act ( NEPA)
Under NEPA, impacts and measures to mitigate adverse impacts must be
identified, including the identification of impacts for which no or only partial
mitigation is possible.
The FHWA regulations in Sec. 1.2.2 constitute the Federal Noise Standard.
Projects complying with this Standard are also in compliance with the
requirements stemming from NEPA
1.2.2 Federal Highway Administration ( FHWA) Regulations
Under FHWA regulations ( 23 CFR 772), noise abatement must be
considered for Type I projects when the project results in a substantial noise
increase ( see Section 2.4.1), or when the predicted noise levels approach or
exceed the Noise Abatement Criteria ( NAC) ( see Section 2.4.2). Noise
abatement measures which are reasonable and feasible and that are likely
to be incorporated in the project, as well as noise impacts for which no
apparent solution is available, must be identified and incorporated into the
project’s plans and specifications ( 23 CFR 772.11( e)( 1) and ( 2)).
1.3 California Requirements
1.3.1 California Environmental Quality Act ( CEQA)
Under CEQA, a substantial noise increase may result in a significant
adverse environmental effect and, if so, must be mitigated or identified as a
noise impact for which it is likely that no, or only partial abatement
measures are available. Specific economic, social, environmental, legal, and
technological conditions may make additional noise attenuation measures
infeasible.
1.3.2 Streets and Highways Code, Section 216
If, as a result of a proposed freeway project, noise levels in classrooms of
public or private elementary or secondary schools exceed 52 dBA, Leq( h) the
Department shall provide noise abatement to reduce classroom noise to the
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criteria or below. If the classroom noise exceeds the criteria before and after
the freeway project, the Department shall provide noise abatement to reduce
classroom noise to pre- project noise levels. The requirements are covered in
the Streets and Highways Code, Section 216.
1.4 Analyses
1.4.1 Project Alternatives
The Protocol applies to the assessment and disclosure of potential impacts
of project alternatives as identified within the scope of an Environmental
Document as required by NEPA/ CEQA. The results of the screening
evaluation and further detailed studies should be incorporated into
environmental documentation or used as part of a major investment study
( MIS) as appropriate.
1.4.2 Timing
As part of the general environmental review process associated with all
projects, project sponsors are required to evaluate if the predicted noise
levels could result in traffic noise impacts ( see Section 2.4), and if so,
consider and implement noise abatement if feasible and reasonable. The
process leading to a preliminary noise abatement decision ( FHWA process)
is contained in Section 2 and the results are reported in the draft
environmental documentation as appropriate.
A noise impact resulting from a substantial noise increase may additionally
be a significant adverse environmental effect. The additional process leading
to a noise abatement or mitigation decision for a significant environmental
effect ( CEQA process) is described in Section 3, and is also reported in the
draft environmental documentation as appropriate.
The final noise abatement/ mitigation decision process, described in Section
4, occurs after the input from impacted residents and local agencies, and
after consideration of social, economic, environmental, legal, and
technological factors.
The date of public knowledge of a proposed transportation project is used to
determine if noise abatement should be considered as part of the project, or
if noise abatement should be the responsibility of local government agencies
or private developers. The date of public knowledge shall be the date of
approval of the final environmental decision document ( e. g. a Record of
Decision).
When traffic noise impacts ( see Section 2.4) are predicted for undeveloped
lands for which development is planned, designed and programmed before
the date of public knowledge, noise abatement must be considered as part
of the project. Development is considered planned, designed and
programmed, on the date that a noise sensitive land- use ( subdivision,
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residences, schools, churches, hospitals, libraries, etc.) has received final
development approval ( generally considered to be the issuance of a building
permit) from the local agency with jurisdiction.
1.4.3 Project Re- analysis
Project noise impacts or consideration of abatement measures may have to
be re- analyzed if one of the following occurs:
a) There has been a significant change in project design concept and/ or
scope from that of the most recent environmental analysis, or
b) A significant period of time has passed since the most recent
environmental analysis, generally considered to be 3 years between
project milestones, e. g. Record of Decision to Right of Way Certification,
or
c) An undeveloped land becomes planned, designed and programmed, after
the analysis, but before the date of public knowledge, or
d) An undeveloped land becomes developed after the date of public
knowledge ( disclosure of impacts, if any, but abatement not considered).
1.4.4 Levels of Traffic Noise Analysis
All proposed projects affected by this Protocol should first be analyzed by
using a screening procedure. The procedure is outlined Sec. 2.2, and
detailed in TeNS Sec. N- 4000.
If the project does not pass the screening procedure, a detailed analysis
should be performed. The detailed analysis consists of two parts: 1) traffic
noise impact analysis and, 2) preliminary noise abatement design. The
procedures are outlined in Sec.’ s 2.3 through 2.6, and are detailed in TeNS
Sec.’ s N- 5000 and N- 6000.
1.4.5 Construction Noise
Construction noise is only substantial in exceptional cases, such as pile
driving and crack and seat pavement rehabilitation operations. Standard
Specifications ( Sections 7 and 42) and Standard Special Provisions provide
limits on construction noise levels and are used as appropriate. Normally,
construction noise levels should not exceed 86 dBA ( LMAX) at a distance of
15 m.
If construction noise on any highway project is anticipated to be a
substantial problem, the following items should be examined during the
project process:
a) Land- uses or activities that may be affected by noise from construction of
a project.
b) Measures necessary to minimize or eliminate adverse construction noise
impacts on the community that could be incorporated in the plans and
specifications.
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1.5 Liaison with Local Agencies
Cities and counties are required to adopt general plans of development for their
communities that must include a noise element, which among other noise
sources, considers the noise emanated from freeways and highways ( CGC
65302). The noise element serves as a guide for establishing a pattern of land-use
development to minimize the exposure of community residents to excessive
noise. Caltrans encourages local agencies to establish compatible zoning that
would preclude noise- sensitive land- uses adjacent to State highways. To
facilitate compatible land- use decisions, Caltrans will provide local agencies
with project noise studies. This may be accomplished via the Inter
Governmental Review ( IGR) process or by direct mailing.
In addition, some communities have established local noise ordinances to
abate nuisance noise. Project contract specifications ( standard or special
provisions) provide that construction activities may be subject to local
ordinances. Efforts should be made to determine the existence of local
ordinances and to what degree they may or may not apply.
The likelihood that the area considered for noise abatement would change
land- use designation within the life cycle of the project should be considered.
Working with the local agency responsible for the land use designation ( i. e.,
city or county) will determine if redevelopment of the subject area ( e. g.
residential to commercial) is a strong possibility. A written statement from the
local agency should be obtained for documentation that redevelopment is
likely. If the area is likely to be redeveloped, it may be prudent to defer
construction of noise abatement until a final decision is known.
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2. PRELIMINARY NOISE ABATEMENT DECISION ( FHWA PROCESS)
For Type I projects traffic noise must be analyzed for all alternatives under
consideration, and traffic noise impacts identified. If traffic noise impacts are
identified, noise abatement must be considered, and feasible and reasonable
abatement measures included in the draft environmental documentation. This
preliminary noise abatement decision process is depicted in Figure 2- 1. The
individual components of this chart are discussed in the following subsections.
2.1 Type I Projects
A Type I project is defined by 23 CFR 772 as follows. A proposed Federal or
Federal- aid highway project for the construction of a highway on a new location,
or the physical alteration of an existing highway which significantly changes
either the horizontal or vertical alignment, or increases the number of through-traffic
lanes. Caltrans extends the Type I definition in 23 CFR 772 to State
highway projects without Federal funding.
FHWA and Caltrans interpretation of the above definition of Type I projects
differ slightly. When there is no FHWA involvement ( such as no federal funding
or not on the National Highway System), “ increases the number of continuous
traffic lanes” refers to an increase in the basic number of continuous traffic
lanes of the highway segment. The Caltrans interpretation of Type 1 Projects
excludes lanes for parking, speed change, turning, storage for turning,
weaving, truck climbing, and other purposes supplementary to through- traffic
movement and ramp widening projects. These projects, however, are still
subject to the provisions of CEQA.
FHWA has clarified their interpretation as quoted from their Protocol comments
and June 1995 Highway Traffic Noise Analysis and Abatement – Policy and
Guidance: “… a Type I project is any project that has the potential to increase
noise levels at adjacent receivers. Such a project specifically creates a totally
new noise source, or increases the volume or speed of traffic or moves the
traffic closer to the receivers… The addition of an interchange/ ramp/ auxiliary
lane/ truck- climbing lane, etc. to an existing highway is considered to be a Type
I project. A project to widen an existing ramp by a full lane- width is also
considered to be a Type I project… Similarly, the addition of high- occupancy
vehicle ( HOV) lanes to highways are also Type I projects, whether added in the
median or on the outside of the existing highway… Traffic noise analysis is
required for both sides of the highway, even when HOV lanes are only added on
one side of the highway… Projects unrelated to increased noise levels, such as
lighting, signing, landscaping, etc., are not considered to be Type I projects.”
Although a project may not comply with the definition of a Type I project, it
may still be treated as a Type I project in extremely rare instances. This occurs
when the project itself is expected to raise traffic noise levels from a non-approach-
or- exceed level to an approach- or- exceed impact, or cause a
substantial noise increase impact ( see Sections 2.4.1 and 2.4.2). An example
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Figure 2- 1 Flow Chart of Preliminary Noise Abatement Decision
NOTE:
E. D. = Environmental Documentation
NO FURTHER
ANALYSIS
NECESSARY
( Report in E. D.)
PERFORM
SCREENING
PROCEDURE
PERFORM
TRAFFIC NOISE
IMPACT
ANALYSIS
DESIGN
PRELIMINARY
NOISE
ABATEMENT
ABATEMENT
RECOMMENDED
ABATEMENT
NOT
RECOMMENDED
PRELIMINARY
NOISE
ABATEMENT
DECISION
( Report in E. D.)
Go to Figure 3.1 if either one or both of the following apply:
a) Traffic Noise Impact is due to a Substantial Noise Increase
b) The proposed noise abatement has potential for a significant effect on a
competing resource such as designated scenic highways, historical sites,
endangered species, etc.
Otherwise, go to Figure 4.1.
Is Project
a Type I
Project?
Pass
Screening
Procedure?
Result
In Traffic Noise
Impact( s)?
Is Noise
Abatement
Feasible?
Is Noise
Abatement
Reasonable?
NO
YES
NO
NO
NO
YES
YES
YES
YES
NO
Sec. 2.1
Sec. 2.2
TeNS N- 4000
Sec. 2.3
TeNS N- 5000
Sec. 2.4
Sec. 2.6
TeNS N- 6000
Sec. 2.7
Sec. 2.8
Sec. 2.9
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of such a situation might be side slopes that are flattened as part of a project to
improve an intersection or improve sight distance.
2.2 Screening Procedure
The screening procedure is intended to determine whether a detailed analysis
is necessary. If a project passes the screening procedure, further analysis is
normally not necessary. In instances when a project is considered
controversial or when the net effects of changes in topography and shielding
are not obvious, a detailed analysis is warranted even if the screening
procedure may indicate otherwise. The complete procedure is covered in TeNS,
Section N- 4000. Following is a summary of the screening procedure steps:
a) Determine if there are potentially impacted receivers. If there are no
impacted receivers, no further analysis will be necessary.
b) Determine if the project will be along an existing alignment or
realignment. If it will be on a new alignment, the screening procedure
cannot be used, and a detailed analysis is required.
c) Determine if shielding ( or lack thereof) of the receivers will be the
same or improved after the project. If it is not, a detailed analysis is
required.
d) Measure the existing worst hourly noise levels at the critical receivers.
If the existing noise levels are less than 5 dBA below the applicable
Noise Abatement Criterion ( Table 2- 1), a detailed analysis is required.
e) If the increase in noise levels after the project is 3 dBA or more above
existing noise levels, a detailed analysis is required. The increase is
calculated from a simple formula involving existing and future traffic,
and existing and future roadway to receiver distances.
2.3 Impact Analysis
If the project fails the screening procedure, or if other conditions discussed in
Section 2.2 apply, a detailed analysis must be performed. The first part of this
analysis is to analyze if traffic noise impacts are predicted. The traffic noise
impact analysis shall include the following for each alternative under detailed
study:
a) Identify existing land use activities, developed lands, and undeveloped
lands for which development is planned, designed and programmed
( see Section 1.4.2), which may be affected by noise from the highway
( TeNS Section N- 5200).
b) Determine highest hourly existing noise levels ( TeNS Section N- 5300)
c) Predict traffic noise levels using traffic characteristics that will yield
the worst hourly traffic noise impact on a regular basis for the design
year and using traffic noise prediction methodology that meets the
following two conditions:
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1) The method is consistent with the FHWA Highway Traffic Noise
Prediction Model ( Report No. FHWA- RD- 77- 108) and,
2) The method uses California Vehicle Noise Emission Levels
( Calveno) ( Report No. FHWA/ CA/ TL- 87/ 03).
TeNS Sections N- 5400 and N- 5500 discuss noise prediction
procedures.
d) Determine traffic noise impacts for areas adjoining the project
( Section 2.4).
2.4 Traffic Noise Impacts
When traffic noise impacts have been identified, noise abatement measures
must be considered.
Traffic noise impacts occur when one or more of the following occur: 1) a
substantial noise increase; 2) predicted noise levels approach or exceed Noise
Abatement Criteria.
2.4.1 Substantial Noise Increase
A noise increase is substantial when the predicted noise levels with the
project exceed existing noise levels by 12 dBA, Leq( h).
2.4.2 Approach or Exceed the Noise Abatement Criteria
A traffic noise impact will also occur when predicted noise levels with project
approach within 1 dBA, or exceed the Noise Abatement Criteria ( Table 2- 1).
Table 2- 1. Activity Categories and Noise Abatement Criteria ( NAC)
Activity
Category
NAC, Hourly A-Weighted
Noise
Level, dBA Leq( h)
Description of Activities
A 57
Exterior
Lands on which serenity and quiet are of
extraordinary significance and serve an
important public need and where the
preservation of those qualities is essential
if the area is to continue to serve its
intended purpose.
B 67
Exterior
Picnic areas, recreation areas,
playgrounds, active sport areas, parks,
residences, motels, hotels, schools,
churches, libraries, and hospitals.
C 72
Exterior
Developed lands, properties, or activities
not included in Categories A or B above.
D -- Undeveloped lands.
E 52
Interior
Residences, motels, hotels, public
meeting rooms, schools, churches,
libraries, hospitals, and auditoriums.
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2.5 School Classroom Noise Impact
A noise impact may also be found if as a result of a proposed freeway project,
noise levels exceed 52 dBA, Leq( h), within the interior of an existing public or
private elementary, or secondary school. Refer to the provisions of the Streets
and Highways Code, Section 216 for applicability. This requirement does not
replace the approach or exceed NAC criterion for FHWA Activity Category E for
classroom interiors ( Section 2.4.2).
If a project results in an impact the Department shall provide noise abatement
to reduce classroom noise to the criteria or below. If the classroom noise
exceeds the criteria both before and after the freeway project, the Department
shall at a minimum provide noise abatement to reduce classroom noise to pre-project
noise levels.
2.6 Preliminary Noise Abatement Design
If traffic noise impacts are predicted, noise abatement measures must be
evaluated and considered ( see Section 5.3). Preliminary noise abatement
design includes acoustical considerations such as noise barrier heights,
lengths, location, material, etc. These are discussed in TeNS Section N- 6000.
2.7 Noise Abatement Feasibility
Feasibility is defined as an engineering consideration. A minimum of 5- dBA-noise
reduction must be achieved at the impacted receivers in order for the
proposed noise abatement measure to be considered feasible. The feasibility
criterion is not necessarily a noise abatement design goal ( see Section 5.2).
Greater noise reductions are encouraged if they can be reasonably achieved.
Feasibility may be restricted by: ( 1) topography; ( 2) access requirements for
driveways, ramps, etc.; ( 3) the presence of local cross streets, ( 4) other noise
sources in the area, and ( 5) safety considerations.
2.8 Noise Abatement Reasonableness
2.8.1 General
The determination of reasonableness of noise abatement is more subjective
than the determination of its feasibility. It implies that common sense and
good judgment have been applied in arriving at a decision. There will be
instances where noise abatement may be found reasonable even though it is
outside the established bounds of reasonableness. The individual
circumstances of each project and consideration of borderline cases should
be part of the overall decision making process.
Noise abatement is only considered where noise impacts are predicted and
where frequent human use occurs and a lowered noise level would be of
benefit. Primary consideration will be given to exterior areas. In situations
where no exterior activities are affected by the traffic noise, or where the
exterior activities are far from, or physically shielded from the roadway and
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therefore not impacted, the interior criterion ( Category E in Table 2- 1) shall
be used as a basis for noise abatement consideration.
The overall reasonableness of noise abatement is determined by considering
a multitude of factors including but not necessarily limited to the following:
a) Cost of the abatement
b) Absolute noise levels
c) Change in noise levels
d) Noise abatement benefits
e) Date of development along the highway
f) Life cycle of abatement measures
g) Environmental impacts of abatement construction
h) Views ( opinions) of impacted residents
i) Input from the public and local agencies
j) Social, economic, environmental, legal, and technological factors
The life cycle of the noise abatement ( above factor ( f)) is a consideration in
the preliminary reasonableness decision. It is normally not reasonable to
construct a wall where planned future use would limit its useful life to less
than 15 years.
Normally, noise abatement is not designed for the second floor level
( Highway Design Manual Chapter 1100). However, noise abatement
designed to provide 5 dBA for the second floor level without exceeding the
modified allowance is within the scope of reasonableness.
The preliminary reasonableness decision is based on the above factors ( a)
through ( f) as described in this section and the following Sections 2.8.2 and
2.8.3. The remaining factors are considered through the public input
process described in Section 4. The environmental impacts of abatement
construction are addressed in Section 3.
2.8.2 Preliminary Reasonableness Determination for Residential Areas in
Activity Category B
The preliminary decision of providing noise abatement for exteriors of
residential areas in activity category B ( see Table 2- 1) is made from a single
dollar value, a reasonable allowance per benefited residence ( see Section 7,
Glossary) that embodies five reasonableness factors. If the abatement can
be constructed for that amount, the preliminary reasonableness decision
will be to provide abatement
The preliminary reasonableness determination of providing noise abatement
for exteriors of residential areas in activity category B ( see Table 2- 1) begins
with a $ 15,000 base allowance per benefited residence. The 1998 base year
allowance is based on a noise barrier cost of $ 151/ m2 ($ 14/ ft2), which
includes costs of the wall, footings, traffic control, drainage, modifying or
adding planting, miscellaneous items and a 10% contingency. A wall length
of 30.5 m ( 100 ft) and a height of 3.05 m ( 10 ft) is assumed to cover the
average residence. This wall height normally provides a 5 dBA noise
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reduction and breaks the line of sight between a 3.5 m ( 11.5 ft) high truck
exhaust stack and a 1.5 m ( 5 ft) high receiver at the first tier of residences,
as required by the Highway Design Manual, Chapter 1100.
The $ 15,000 base allowance may be updated every two years using the
Construction Cost Index as calculated by the Office of the Office Engineer,
and rounded to the nearest one thousand dollars.
The base cost per benefited residence will be adjusted by the five
reasonableness factors explained in the following pages. The terms used in
these reasonableness factors are explained in Section 7 Glossary.
For each noise abatement facility ( noise barrier) location the base allowance
of $ 15,000 ( 1998) per benefited residence is adjusted by the following
reasonableness factors. The final result will be the reasonable allowance per
residence for the noise abatement facility, taking into consideration the
following five reasonableness factors:
1) Absolute Noise Levels. These are predicted future noise levels ( with
project, but without noise abatement) at the critical design receiver( s). If
the absolute noise levels are:
69 dBA or less: add $ 2,000
70- 74 dBA: add $ 4,000
75- 78 dBA: add $ 6,000
More than 78 dBA: add $ 8,000
( Choose one only)
2) “ Build” VS Existing Noise Levels. This is the increase in noise levels of
the future predicted ( with project) over existing noise levels at the critical
design receivers. If the increase is:
Less than 3 dBA: add $ 0
3- 7 dBA: add $ 2,000
8- 11 dBA: add $ 4,000
12 dBA or more: add $ 6,000
( Choose one only)
3) Achievable Noise Reduction. This is the noise reduction ( e. g. noise
barrier insertion loss) provided by the noise abatement at the critical
design receivers. If the noise reduction is:
Less than 6 dBA: add $ 0
6- 8 dBA: add $ 2,000
9- 11 dBA: add $ 4,000
12 dBA or more: add $ 6,000
( Choose one only)
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4) New Construction, or Predate 1978. If the project is new highway
construction, or if the majority of benefited residences ( more than 50%) were in
existence before January 1, 1978 for a highway reconstruction.
If:
YES on either one: add $ 10,000
If NO on both: add $ 0
( Choose one only)
5) Total Noise Abatement Allowance VS Project Cost. The final
reasonableness factor, based on the ratio of the total allowance ( AT) for
noise abatement versus the cost of the project without noise abatement
( CP) may result in a modified reasonable allowance ( Am). AT is calculated
from the base cost plus adjustments ( 1) through ( 4) ( A) for each
abatement facility ( e. g. noise barrier) location ( i), multiplied by the
number of benefited residences ( N) for each location ( i) and summed for
all locations ( n) and is expressed mathematically as:
and represents the total allowance ( AT) for noise abatement on the
project.
If the ( AT) is no more than 50% of the estimated project cost ( CP), the
reasonable allowance per residence is Ai, and no further modification is
necessary. This condition is expressed as:
If the total allowance for noise abatement exceeds 50% of the cost of the
project, the above expression is greater than 0. The positive result is the
total allowance excess ( ET) and is expressed as:
If there is an excess allowance as described above, the reasonable
allowance per residence at each noise abatement location is reduced as
follows:
i
T T
i i
mi i N
A E
N A
A A
( )( )
= -
å =
= n
i 1
AT ( NiAi )
E A ( 0.5C ) 0 ( Modification necessary) T T p = - >
A ( 0.5C ) 0 ( No modification necessary) T p - £
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The modified reasonable allowance per benefited residence for each noise
abatement location ( Ami) is a dollar value that always is greater than zero.
This final dollar value embodies five reasonableness factors and is the basis
for the preliminary noise abatement decision at that location. Ami should
therefore not be construed as one cost effectiveness factor to be weighed
with other factors in the preliminary abatement decision. The initial base
allowance of $ 15,000 complies with the FHWA minimum cost effectiveness
requirement.
The estimated actual cost per residence of the proposed noise abatement for
a location should be at or below the modified ( if necessary) reasonable
allowance per residence for the noise abatement to be reasonable for that
location. The cost calculations of the noise abatement should include all
items appropriate and necessary for the construction of the noise abatement
facility ( e. g. noise barrier), such as traffic control, drainage modification,
retaining walls, etc.
The reasonable allowance ( modified or unmodified) as discussed in this
section is calculated independently from the estimated cost per benefited
residence discussed in the previous paragraph. The reasonable allowance
should be used for comparative purposes only and is considered the
maximum amount that should reasonably be spent on noise abatement. It
should not be construed as a spending goal. If the estimated cost of the
noise abatement per benefited residence turns out to be below the
reasonable allowance per benefited residence and the noise abatement goals
( Section 5.2) will be met, no attempt should be made to increase spending
for noise abatement to the maximum of the reasonable allowance.
An example of the modified reasonable allowance calculation on the basis of
the above reasonableness factors ( 1) through ( 5), and suggested worksheets
is shown in Appendix B.
2.8.3 Preliminary Reasonableness Determination For Non- Residential Areas
in Activity Category B, and Other Activity Categories
a) For schools, churches, hospitals, hotels, motels, and other potentially
noise sensitive buildings in land use category B ( Table 2- 1), the concepts
of reasonableness determination for residences ( Section 2.8.2) may be
applied. The same base allowance ($ 15,000), adjustments and
modifications explained in Section 2.8.2 will be used in the
determination of reasonableness, except that instead of residential units
30.5 m ( 100 ft) frontage units are used. This method ensures the same
consideration of the severity of impacts as used in residential areas.
b) For parks, recreational and picnic areas in land use category B ( Table 2-
1), only the areas of frequent human use will be considered for noise
abatement. These areas will be treated the same as under ( a) in this
section with the same frontage units calculated for frontages of impacted
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areas of frequent human use and where a lowered noise level would be of
benefit. This method preserves the same consideration of severity of
impacts as in a) and Section 2.8.2.
c) Lands on which serenity and quiet are of extraordinary significance
( Category A, Table 2- 1) are rare, and reasonableness of noise abatement
should be determined on a case- by- case basis.
In addition to the cost, factors that must be considered are:
· Importance with respect to public need
· Importance of the serene and quiet qualities with respect to the area’s
intended purpose
· Frequency of human use
d) Noise abatement is normally not considered reasonable for commercial
areas.
e) Noise abatement is not considered reasonable for parking lots. These
facilities are intended for transient use only.
f) Reasonableness of noise abatement for residence interiors ( Category E,
Table 2- 1) should be considered using the same factors as in Section 2.8.2,
using exterior noise levels to determine the adjustment for absolute noise
levels. For interiors of schools, churches, hospitals and other potentially
sensitive buildings, the same factors as in ( a) should be used to arrive at a
preliminary reasonableness decision.
2.9 Preliminary Noise Abatement Decision and Reporting
After completing the preliminary noise abatement decision process depicted in
flowchart 2.1, a decision is made based on the findings determined during the
process. There are three possible outcomes:
a) If the project is exempt from analysis per Section 2.1, or if there are no
traffic noise impacts predicted, no further analysis is necessary. Report
in the project’s environmental documentation that no traffic noise
impacts are predicted.
b) If traffic noise impacts are predicted and the proposed noise abatement is
feasible and reasonable, abatement will be recommended. The
preliminary decision is reported in the applicable environmental
documentation with the following cautionary note:
Based on the studies so far accomplished, Caltrans intends to
incorporate noise abatement measures in the form of ( a) barrier( s)
at: ________________________________________________________,
with respective lengths and average heights of:
____________________ Calculations based on preliminary design
data indicate that the barrier( s) will reduce noise levels by 5 to
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___ dBA for______ residences at a cost of:__________ If during
final design conditions have substantially changed, noise
barriers might not be provided. The final decision of the noise
barriers will be made upon completion of the project design and
the public involvement processes.
c) If traffic noise impacts are predicted, but the proposed noise abatement
is not feasible or reasonable, noise abatement will not be recommended.
Report that traffic noise impacts exist for which no apparent solutions
are available, the reasons why, and that the impacts will not cause a
significant adverse environmental effect.
The process in Section 4 finalizes the preliminary decision. Procedures covered
in Section 3 must first be followed before reporting the preliminary decision, if
the potential exists for a significant adverse environmental impact due to either
one or both of the following:
· Traffic noise impacts predicted in either ( b) or ( c) are due to substantial
noise increases.
· The proposed noise abatement in ( b) has a potential for a significant effect
on a competing resource such as designated scenic highways, scenic vistas,
historical sites, endangered species, etc.
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3. PRELIMINARY NOISE ABATEMENT/ MITIGATION DECISION ( CEQA
PROCESS)
This decision process examines whether the project or proposed abatement
measures result in a significant adverse environmental effect. Either one or
both of the following trigger this process:
· Traffic noise impacts predicted are due to substantial noise increases.
· Proposed noise abatement has a potential for a significant effect on a
competing resource such as a designated scenic highway, a historical site,
an endangered species, etc.
Figure 3.1 shows both situations entering the flowchart. The process
addresses requirements under the California Environmental Quality Act
( CEQA).
3.1 Traffic Noise Impact Due To A Substantial Noise Increase
If the predicted traffic noise levels after the proposed project are expected to
result in a substantial noise increase over the existing noise levels there is a
potential for the proposed project to cause a significant adverse environmental
effect due to noise. This will be evaluated in Section 3.2.
3.2 Does Project Result In A Significant Adverse Environmental Effect Due To
Noise?
To determine if the substantial noise increase is a significant adverse
environmental effect, consideration must be given to the context and intensity
of the substantial noise increase. Context refers to the project setting and
uniqueness, or sensitive nature of the noise receiver( s). Intensity refers to the
project induced substantial noise increase, i. e. the increase over the “ no- build”
condition; it also refers to the number of residential units affected and to the
absolute noise levels.
3.2.1 Project Results In A Significant Adverse Environmental Effect Due To
Noise
If the project- generated substantial noise increase is expected to cause a
significant adverse environmental effect the procedures in Section 3.3 must
be followed.
3.2.2 Project Does Not Result In A Significant Adverse Environmental Effect
Due To Noise
If the project- generated substantial noise increase does not cause a
significant adverse environmental effect go to Section 3.5.
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Figure 3- 1 Flow Chart of Preliminary Noise Mitigation/ Abatement Decision
Does Noise
Abatement itself
Result in
SAEE?
NOTE:
E. D. = Environmental Documentation
SAEE= Significant Adverse Environmental Effect
EVALUATE IF NOISE
ABATEMENT SIGNIFICANTLY
AFFECTS AN OTHER
RESOURCE, RESULTING IN
SAEE
Does
Project Noise
Result in a SAEE?
EVALUATE IF PROJECT
RESULTS IN A SAEE DUE
TO NOISE
PRELIMINARY NOISE
ABATEMENT DECISION
( From Bottom of Figure 2.1)
a) TRAFFIC NOISE IMPACT
IS DUE TO A
SUBSTANTIAL NOISE
INCREASE
b) PROPOSED NOISE
ABATEMENT HAS
POTENTIAL FOR A
SIGNIFICANT EFFECT ON
COMPETING RESOURCE
NO
YES
NO
YES
DEVELOP OVERALL
MITIGATION PLAN
( Report in E. D.)
Go to Figure 4.1
PRELIMINARY NOISE
MITIGATION/ ABATEMENT
DECISION
To
Figure 4.1
Sec. 3.1 Sec. 3.4
Sec. 3.2
Sec. 3.3 Sec. 3.6
Sec. 3.5
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3.3 Preliminary Noise Mitigation Decision And Development Of An Overall
Mitigation Plan
The traffic noise impact caused by the project is expected to be a significant
adverse environmental effect, and mitigation must be considered under CEQA
requirements. It must be further evaluated whether the proposed noise
mitigation itself will result in a significant adverse environmental effect.
3.3.1 Noise Mitigation Does Not Result in Significant Adverse Environmental
Effect
If the noise mitigation is not expected to cause a significant adverse
environmental effect, report in the Draft Environmental Document that
noise mitigation will be a condition of project approval. Include likely noise
mitigation measures, general location and dimensions ( height and length),
noise reduction, and cost of the noise mitigation facility ( e. g. noise barrier).
Also identify significant adverse noise effects for which it is likely that no, or
only partial mitigation measures are available, including specific economic,
social, environmental, legal, and technological conditions which make
infeasible additional noise mitigation measures. Go to Section 4 for the final
mitigation decision.
3.3.2 Noise Mitigation Results in a Significant Adverse Environmental Effect
If the noise mitigation is expected to result in a significant adverse
environmental effect ( such as by causing a visual intrusion on a scenic
highway, blocking resident’s views, adverse effects on historical sites, etc.),
an overall mitigation plan must be developed. The plan should include
consideration of competing environmental resources. To accomplish this,
sufficient information regarding the physical characteristics, benefits, and
detriments of the proposed mitigation is necessary so that it can be
balanced against the affected resource( s). Go to Section 4 for the final
mitigation decision.
3.4 The Proposed Noise Abatement Has Potential For A Significant Effect On
Competing Resource( s)
In Section 2.9 it was determined that, although the project- generated noise
increase was not substantial, the proposed noise abatement has a potential for
a significant effect on a competing resource such as designated scenic
highways, scenic vistas, historical sites, endangered species, etc.
3.5 Does Noise Abatement Significantly Affect Another Resource, Resulting In
A Significant Adverse Environmental Effect?
If the project- generated noise does not cause a significant adverse
environmental effect and proposed noise abatement may negatively affect one
or more competing resources such as designated scenic highways, scenic
vistas, historical sites, endangered species, the abatement itself may cause a
significant adverse environmental effect.
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As was the case with the substantial noise increase ( Section 3.2), the
significance of the effect must be evaluated in terms of the context and
intensity. In this case, the context of the noise abatement ( e. g. noise barrier)
refers to how it blends in with the environment ( e. g. visual blight in a scenic
area), whether it blocks the views of residents as well as those of the motorists
( scenic highway), etc. The intensity refers to the amount of resource users are
affected and the extent of the detrimental affects of the abatement ( such as
shadows, redirecting airflow, changes in microclimate and temperature, or
other environmental effects).
3.5.1 Noise Abatement Does Not Result in a Significant Adverse
Environmental Effect
If the proposed noise abatement itself does not affect any other resources go
to Section 4.
3.5.2 Noise Abatement Results in a Significant Adverse Environmental Effect
If the noise abatement is expected to result in a significant adverse
environmental effect ( such as by causing a visual intrusion on a scenic
highway, blocking resident’s views, adverse effects on historical sites, and
changes in microclimate etc.), go to Section 3.6.
3.6 Preliminary Noise Abatement Decision And Development Of An Overall
Mitigation Plan
An overall mitigation plan must be developed and reported in the
Environmental Document ( see Sec. 3.3.1 and 3.3.2 for reporting requirements).
The plan should include consideration of competing environmental resources.
To accomplish this, sufficient information regarding the physical
characteristics, benefits, and detriments of the proposed mitigation is
necessary so that it can be balanced against the affected resource( s). Go to
Section 4 for the final abatement decision.
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4. FINAL NOISE ABATEMENT/ MITIGATION DECISION ( FHWA AND
CEQA PROCESS)
The flow chart in Figure 4- 1 shows the process of reporting the preliminary
noise abatement/ mitigation decision and soliciting public input, including the
views of impacted residents, local agencies, social, economic, environmental,
legal, and technological factors. The preliminary decision and the public input
process form the basis for the final noise abatement/ mitigation decision.
4.1 Environmental Documentation
The appropriate environmental documentation ( e. g. Draft Environmental
Impact Statement, Draft Negative Declaration etc.) serves as a vehicle to
circulate the preliminary noise abatement/ mitigation decision. If noise
abatement/ mitigation is proposed the design is based on preliminary project
alignments and profiles, which may be subject to change. The document
should report that the physical characteristics of the abatement/ mitigation
( e. g. length, height, location and material of noise barrier) are preliminary and
should be accompanied with a statement such as the following:
If pertinent parameters change substantially during the final project design,
the preliminary noise abatement/ mitigation design may be changed or
eliminated from the final project design. A final decision of the construction of
the noise abatement/ mitigation will be made upon completion of the project
design.
If the project will have a significant adverse environmental effect due to noise,
the proposed noise abatement measure is called noise mitigation. Otherwise, it
should be referred to as noise abatement.
4.2 Public Input Process
Views ( i. e. opinions) of the impacted residents will be a major consideration in
reaching a final decision on the reasonableness of abatement measures to be
provided. The opinions of these residents should be obtained through public
hearings, community meetings or other means as appropriate. Use of visual
simulations to show impacts created by barriers is recommended.
Public hearings and community meetings also serve as a vehicle for other
public input, such as views of motorists, other members of the community, and
local agencies. The latter must be consulted on newly approved developments,
planned, designed and programmed ( see Section 1.4.2).
4.3 Final Noise Abatement Decision And Final Environmental Document
The final noise abatement decision is a product of public input as well as the
preliminary noise abatement decision. It is a component of the project’s overall
environmental decision making process.
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Figure 4- 1 Flow Chart of Noise Abatement/ Mitigation Decision
PRELIMINARY
NOISE
ABATEMENT
DECISION
( From Figure 2.1)
PRELIM. NOISE
MITIGATION/
ABATEMENT
DECISION
( From Figure 3.1)
ENVIRONMENTAL
DOCUMENTATION
PUBLIC INPUT PROCESS
INPUT FROM
IMPACTED
RESIDENTS
PUBLIC & LOCAL
AGENCY INPUT
SOCIAL, ECONOMIC,
ENVIRONMENTAL,
LEGAL, AND
TECHNOLOGICAL
FACTORS
FINAL NOISE
ABATEMENT/
MITIGATION
DECISION
FINAL
ENVIRONMENTAL
DOCUMENT
Sec. 4.1
Sec. 4.2
and 4.3
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Although the Draft Environmental Document serves as a starting point in the
final noise abatement decision, the decision maker has an obligation to balance
a variety of public objectives. These include specific economic, environmental,
social, legal, and technological factors as well as other public opinions and the
views of the impacted residents.
If noise abatement is proposed, consideration must be given to the opinions of
the adjacent resident owners, such as whether they favor the construction of
the proposed noise abatement facilities, materials to be used, final appearance,
etc. In the case of rental or leased property, the owners’ opinion are superior to
that of the residents.
Noise abatement will not be provided if 50% or more of the affected residents
do not want it. The opinions of those affected residents should also be
considered regarding the heights of proposed noise barriers. If the majority of
those residents object to a proposed height, the barrier may be constructed at
lower height under certain conditions. The affected residents should be
informed of the proposed height of the noise barrier determined necessary by
noise analysis. If they request a lower noise barrier, the shorter height may be
constructed if it still will reduce the noise by a minimum of 5 dBA. The final
abatement decision is reflected in the Final Environmental Document.
If the reported preliminary abatement/ mitigation design changes after approval
of the Final Environmental Document, a project reanalysis may be necessary
( Section 1.4.3).
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5. NOISE ABATEMENT
5.1 Noise Abatement Objectives
The objectives of noise abatement are shown in the Highway Design Manual,
Chapter 1100, Highway Traffic Noise Abatement, Index 1101.2 ( see Appendix
A).
5.2 Noise Abatement Design Goals
a) If a traffic noise impact is not found to be a significant adverse
environmental effect, the project sponsor shall identify and implement all
reasonable and feasible noise abatement measures. These noise
abatement measures are considered project features. The abatement
must provide a substantial noise reduction, defined as a minimum of 5
dBA for the impacted receivers. Greater noise reductions are encouraged
as long as they can be achieved under the reasonableness guidelines
covered in Section 2.8. If a noise barrier is designed, the end locations of
the barrier should be influenced only by the impacted receivers, and not
by any potentially benefited receivers ( defined in Section 7, Glossary)
flanking the barrier. The Noise Abatement Criteria in Section 2.4.2,
Table 2- 1 should not be used as design goals for noise abatement.
b) If a traffic noise impact is found to be a significant adverse environmental
effect the project sponsor shall identify and implement all abatement
measures to reduce the noise increase below the threshold level of
significance. These are considered mitigation measures and are the
conditions of project approval. If these measures are insufficient to
eliminate the significance, the project sponsor shall implement all
measures that would lessen the significance, and make a finding that
specific economic, environmental, legal, social or technological factors
make additional project alternatives or mitigation measures infeasible.
5.3 Noise Abatement Measures
Noise abatement measures may include, but are not limited to:
a) Avoiding the project impact by using design alternatives that result in
lessening the noise effect, such as altering horizontal and vertical
alignments to avoid a noise impact.
b) Constructing noise barriers ( sound walls and earth berms).
c) Acquiring property or interest to serve as a buffer zone to preempt
development which would be adversely impacted by traffic noise. An
example would be a small set- back from a highway in cut, which would
significantly increase the shielding effect by the top of cut.
d) Using Traffic Management Measures that are consistent with State
Statutes regarding the regulation of traffic control devices, vehicle types,
time use restrictions, modified speed limits, etc.
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e) Insulating and/ or air- conditioning public use or nonprofit institutional
structures.
5.4 Ultimate Location
Noise barriers should be constructed at the ultimate location to accommodate a
full standard facility or approved permanent nonstandard facility, meeting the
transportation concept for the number of lanes, when reasonable or feasible. A
noise barrier is normally not constructed where planned future construction
would limit its useful life to less than 15 years. If the route concept indicates
the freeway will be widened, and the noise barriers are currently to be
constructed adjacent to the shoulder, the design should provide for salvage in
the future.
5.5 Noise Abatement Outside the Right of Way
Noise abatement facilities are normally constructed within the State highway
right of way. However, under certain topographical and geometric
configurations it may be more practical and effective to construct the noise
barrier outside the right of way on private property.
This policy regarding the possibility of constructing noise barriers outside the
right of way applies to all State highway projects regardless of funding for those
projects. When it is determined that noise abatement should be considered for
properties adjacent to the freeway, and when it is found to be more reasonable
and feasible to construct a noise barrier for that abatement outside the State
highway right of way, such construction may be implemented under the
following conditions.
For a proposed barrier location outside of the State highway right of way, a
permanent easement must be secured for all ( 100%) of the affected properties
to construct and maintain the barrier. On a federally funded project, the
FHWA will hold Caltrans responsible for structural maintenance of the
barriers. The acquisition of this permanent easement is part of the
“ reasonableness” ( reasonable allowance per residence) determination for the
abatement. If the noise abatement is determined not to be reasonable, the
property owner may donate the permanent easement by signing a waiver of just
compensation. Because noise abatement is a consideration and not a
requirement, requesting donation of a permanent easement from the property
owner, when noise abatement is determined not to be reasonable, is not a
violation of the Uniform Act.
Additionally, all ( 100%) of the affected property owners must be supportive of
the proposed noise attenuation ( barrier), the location and the materials to be
used for construction.
Each affected property owner must enter into a contract with Caltrans which
specifies that they:
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· Agree to allow Caltrans personnel, representatives and contractors to enter
upon their property for purposes of constructing the noise barrier and all
other related work.
· Agree to allow Caltrans personnel and representatives to enter upon their
property with appropriate prior notification for the purpose of periodic
inspection or structural repair of the barrier.
· Agree to accept aesthetic maintenance responsibility of their respective
portion of the noise barrier upon its completion, and that the barrier’s initial
aesthetic qualities will be perpetuated.
· Agree not to remove the noise barrier without full consent of all other
affected property owners and Caltrans.
· Agree that the contract provisions will be a permanent burden upon the
property involved. The District Right of Way Branch will determine specific
wording which, as a minimum, should include these provisions:
" The term of this contract shall be a burden which runs with the land,
and shall inure and be binding upon the successors, assigns or
transferees of the property owner."
“ The undersigned knowingly waives the right to just compensation.”
( When appropriate).
All parties to the contract must agree to record the document in the official
records of the appropriate County Recorder’s office.
5.6 Unusual and Extraordinary Abatement
Unusual and extraordinary noise abatement strategies such as providing noise
insulation of residential units are rarely employed. Noise insulation will not
normally be provided in private residential dwellings, and may be provided only
when severe traffic noise impacts are anticipated and normal abatement
measures are physically not feasible or are economically unreasonable. When
considering extraordinary abatement measures, it must be demonstrated that
the affected activities experience traffic noise impacts to a far greater degree
than other similar activities adjacent to highway facilities; i. e., private
residential dwelling units will have after- project exterior noise levels of 75 dBA,
Leq( h), or more, or the project causes a noise level increase of 30 dBA or more
over predicted noise levels if no project was constructed. Noise insulation
proposed in accordance with these criteria, on a Federal- aid project, is subject
to approval of the FHWA on a case by case basis. When noise abatement is
provided for public or private properties in line with this policy, an agreement
must be entered into with the owner of the subject property which specifies
that Caltrans is not responsible for any future costs of operating and/ or
maintaining the noise abatement improvements; i. e., air conditioning, caulking,
etc.
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5.7 Aesthetics Elements of Noise Abatement Features
Use of plants as aesthetic components of noise barriers should be considered.
The objective is to reduce life cycle costs of the improvements. Plantings
should be used to combat graffiti and enhance public acceptance.
When landscaping will eventually screen a substantial portion of the sound
wall, only a minimal aesthetic treatment of the barrier is justified. Standard
aesthetic treatments can be found in the Bridge Standard Plans.
When plants or aesthetic features are integral elements of the abatement
feature, they will be considered part of the barrier for reasonableness
consideration.
Where plants are to be used as a cover or appliqué for aesthetics and graffiti
control, or where aesthetic treatments are considered, the District should
involve the local community, which has a strong interest in protecting the
community’s image, and seek participative involvement in protecting the plants
or aesthetic treatment from vandalism.
Planting as an element or component of a noise barrier is not subject to the
funding limitations for Standard Highway Planting.
5.8 Value Analysis and Life- Cycle Cost Analysis
Value Analysis ( VA) studies should be considered for all noise barriers. The VA
studies should consider that the basic aim is to achieve satisfactory noise
reduction. Specific considerations are:
a) Are there non- barrier alternatives?
b) Can part or all of the noise reduction be achieved using an earth mound
( berm)?
c) Are there materials or systems that would be acceptable at this location
that have not been tried previously?
d) Can relocating the wall eliminate the need for a safety shape barrier?
e) Is the barrier located so that future maintenance costs will be
minimized?
f) Can the cost for aesthetic treatments be reduced or eliminated by
judicious use of planting?
g) Is the barrier designed for the ultimate route concept?
These are only a few of the questions, which an innovative VA team should
consider.
Project files for any project that incorporates a noise barrier should include the
justification and background for the design type or the options allowed.
Beyond the basic questions addressed in a VA study, a Life- Cycle Cost Analysis
should be conducted for the types of noise barriers considered. A number of
factors are involved in planning, designing, constructing and maintaining noise
barriers. Because some of these are difficult to evaluate, a list of them should
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be used to test barriers being studied and to justify the material type selected.
The analysis may be different for a given design type depending on whether it is
nearer the traveled way or the right of way line. Life- cycle costs include all
associated costs, such as planting, landscape maintenance and irrigation
costs.
The Value Analysis and Life- Cycle Cost Analysis should be conducted before
any presentations of noise abatement options to the public, and should be the
basis for the alternatives presented.
5.9 Noise Abatement Design Criteria and Considerations
Design criteria for noise abatement facilities are covered in detail in Appendix
A, which contains the Caltrans Highway Design Manual, Chapter 1100, Noise
Abatement.
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6. REFERENCES
1. TeNS - Technical Noise Supplement, Caltrans, Environmental Program,
Noise, Air Quality, and Hazardous Waste Management Office, October
1998
2. NEPA - National Environmental Policy Act of 1969; 42 US Code, sections
4321 - 4370.
3. CEQA - California Environmental Quality Act of 1970; Public Resources
Code Division 13, sections 21000 - 21177.
4. 23 CFR 772 - Title 23, United States Code of Federal Regulations, Part
772.
5. HDM 1100 - Caltrans Highway Design Manual, Chapter 1100, “ Highway
Traffic Noise Abatement”, 5th Edition, July 1, 1995.
6. CGC 65302 - California Government Code Section 65302.
7. FHWA - RD- 77- 108 - FHWA Highway Traffic Noise Prediction Model,
Federal Highway Administration, Office of Research, Office of
Environmental Policy, December 1978.
8. FHWA/ CA/ TL- 87/ 03 - California Vehicle Noise Emission Levels ( Final
Report), Caltrans, Office of Transportation Laboratory, January 1987.
9. Highway Traffic Noise Analysis and Abatement – Policy and Guidance,
Federal Highway Administration, Office of Environment and Planning,
Noise and Air Quality Branch, Washington, D. C., June 1995.
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GLOSSARY
Benefited residence - A dwelling unit expected to receive a noise reduction of
at least 5 dBA from the proposed noise abatement measure. A multi- story
residence counts as one benefited residence even if the proposed noise
abatement provides 5 dBA for the exterior ( e. g. balconies) of two or more
floors. The definition is primarily used in the determination of noise
abatement reasonableness ( Sec’s 2.8.2 and 2.8.3).
Critical design receiver( s) - Depending on the context in which it is used, the
design receiver( s) that is ( are) impacted and for which the absolute noise
levels, build vs. existing noise levels, or achievable noise reduction will be at
a maximum where noise abatement is considered. The definition is
primarily used in the determination of noise abatement reasonableness
( Sec’s 2.8.2 and 2.8.3).
Date of public knowledge - The date that a project is approved, i. e. approval
of the final environmental documentation is completed ( e. g. Record of
Decision).
dBA, dB( A) - Unit of sound pressure level in decibels on the “ A- weighted”
Scale.
Design receiver - Any receiver used in the noise impact analysis, and / or
noise abatement design. Normally, a design receiver represents several or
more locations judged to receive approximately the same predicted noise
levels, the same build vs. existing noise levels, and/ or the same achievable
noise reduction where noise abatement ( e. g. sound wall) is considered.
Existing noise level( s) – The noise, resulting from the natural and
mechanical sources and human activity, considered normally present in a
particular area.
FHWA Type I Project - A proposed Federal or Federal- aid highway project for
the construction of a highway on a new location, or the physical alteration
of an existing highway which significantly changes either the horizontal or
vertical alignment, or increases the number of through- traffic lanes.
Caltrans extends this Type 1 definition to State highway projects without
Federal funding.
Impacted receivers - Receivers that will receive a traffic noise impact ( Section
2.4).
Leq( h) - The equivalent steady- state sound level that, in a specific hour,
contains the same acoustic energy as a time- varying sound level during the
same hour.
Noise Abatement – Noise attenuation provided for non- significant adverse
environmental effects due to noise.
Noise Mitigation – Noise attenuation provided for significant adverse
environmental effects due to noise.
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Planned, designed and programmed - A noise sensitive land- use
( subdivision, residences, schools, churches, hospitals, libraries, etc.) is
considered planned, design and programmed when it has received final
development approval ( generally the issuance of a building permit) from the
local agency with jurisdiction.
Predicted noise level( s) – Future noise levels, resulting from the natural and
mechanical sources and human activity, considered being usually present
in a particular area, including the project.
Receivers - Locations selected for determining traffic noise impacts. These
locations should represent areas where frequent human use occurs, or is
likely to occur in the foreseeable future ( e. g. vacant property for which
development plans have received final approval).
School Classroom Noise Impact – Occurs when a freeway project causes
interior noise levels of an existing public or private elementary or secondary
school to exceed Leq( h) 52 dBA ( See Section 2.5 of this Protocol and Streets
and Highways Code, Section 216).
Traffic Noise Impact - Impact that occurs at a receiver when one or both of
the following takes place:
1) The predicted noise level substantially exceeds ( Section 2.4.1) the existing
noise level.
2) The predicted noise level with the project approaches or exceeds ( Section
2.4.2) the Noise Abatement Criteria ( NAC).
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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October, 1998
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APPENDIX A – DESIGN CRITERIA ( HIGHWAY DESIGN MANUAL
CHAPTER 1100)
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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Highway Design Manual
CHAPTER 1100
HIGHWAY TRAFFIC NOISE ABATEMENT
Topic 1101 - General Requirements
1101.1 - Introduction
The abatement of highway traffic noise is a design consideration that is
required by State and Federal Statutes and regulations and by Caltrans policy.
This chapter provides design standards relating to the location, height and
length of noise barriers and includes discussion on alternative designs,
maintenance and emergency access considerations and aesthetics of noise
barriers. Procedures and policies on minimum attenuation, design goals,
assessing noise impacts, noise abatement criteria levels, priorities,
reasonableness and feasibility, and cost- effectiveness are contained in the
Traffic Noise Analysis Protocol and the Technical Noise Supplement.
1101.2 Objective
The objectives are: for new construction or reconstruction of highways, to limit
the intrusion of highway noise into adjacent areas; on existing freeways to limit
the noise intrusion to achievable levels within practical and financial
limitations; and to limit the noise to the levels specified by statute for qualifying
schools adjacent to freeways. To achieve these objectives the Department
supports the following four approaches to alleviate traffic noise impacts:
( 1) Reduction at the Source. Reduction of traffic noise at the source is the
most effective control. Therefore, Caltrans encourages and supports
legislation to require reduction in motor vehicle noise as advances in the
state- of- the- art of motor vehicle engineering permit.
( 2) Encouraging Compatible Adjacent Land Use. Caltrans encourages those
who plan and develop land and local governments controlling development
or planning land use near known highway locations to exercise their powers
and responsibility to minimize the effect of highway vehicle noise through
appropriate land use control. For example, cities and counties have the
power to control development by the adoption of land use plans and zoning,
subdivision, building and housing regulations.
( 3) Noise Abatement. Caltrans will attempt to locate, design, construct, and
operate State highways to minimize the intrusion of traffic noise into
adjacent areas. When this is not possible, noise impacts may be attenuated
by the construction of noise barriers.
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( 4) Noise Abatement by Others. An increasing number of requests are being
made to Caltrans by owners or developers to attenuate noise reaching
adjacent properties for which the State's mitigation priority is low or
nonexistent. The general policy is that all feasible steps must be taken in
the design of the adjacent development to attenuate noise so as not to
require encroachment on the State's right of way. The State shall assume
NO review authority or responsibility of any kind for the structural integrity
or the effectiveness of the sound attenuation of walls constructed by others
outside of the State's right of way. Where it is determined to be necessary to
permit others to construct a sound barrier within the State's right of way,
the general policy is that the design will meet Caltrans geometric,
structural, and safety standards as established in this and other manuals
and that the effects of the barrier on operation, maintenance and aesthetics
of the highway will be more beneficial than detrimental.
1101.3 Terminology
The terms " noise barrier" and " sound wall" are often used interchangeably.
Technically, a " noise barrier" may be any feature which blocks, prevents or
diminishes the transmission of noise. An earth berm could serve this purpose.
A large building could serve as a noise barrier to shield receptors further from
the noise source. A dense growth of vegetation, if it were wide enough and
dense enough, would be a noise barrier. A " sound wall" is a particular type of
noise barrier. It is a wall, which may be constructed of concrete panels,
masonry blocks, wood boards or panels, or a variety of other materials.
1101.4 Procedures for Assessing Noise Impacts
Highway traffic noise impacts are identified in the project noise study report
and are listed in the environmental document. The procedures for assessing
noise impacts for new highway construction or reconstruction projects, retrofit
projects ( Community Noise Abatement Program - HB311) along existing
freeways, and School Noise Abatement Projects ( HB312), are included in Title
23, United States Code of Federal Regulations Part 772, the Project
Development Procedures Manual, and Section 216 of the Streets and Highways
Code.
1101.5 Prioritizing Construction of Retrofit Noise Barriers
Legal requirements and procedures for prioritizing the construction of noise
attenuation barriers are provided in Section 215.5 of the Streets and Highway
Code.
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
For New Highway Construction and Highway Reconstruction Projects
October, 1998
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Highway Design Manual
CHAPTER 1100
HIGHWAY TRAFFIC NOISE ABATEMENT
Topic 1102 – Design Criteria
1102.1 General
This section covers the noise barrier location, various design aspects such as
height and length of noise barriers, alternative designs, maintenance
considerations, and aesthetic considerations. Various types of Caltrans
standard noise barrier designs are referenced. Noise level criteria and barrier
design procedures, from the acoustical standpoint, are included in the Caltrans
Traffic Noise Analysis Protocol and Technical Noise Supplement.
1102.2 Noise Barrier Location
( 1) Lateral Clearances. Minimum lateral clearance to noise barriers shall
be as provided in Topic 309.1, Horizontal Clearances, of this manual,
but shall not be less than 3 m. Lateral clearances greater than the
minimums should be used whenever feasible. Where terrain permits, the
most desirable location for a noise barrier from a safety perspective is just
inside the right of way or, alternatively, 10 m or more from the traveled way.
When lateral clearance is 4.5 m or less, the noise barrier shall be placed
on a safety shape concrete barrier. Guardrail or safety shape barrier
protection should be considered when the noise barrier is located between
4.5 m and 9 m from the edge of the traveled way.
When the noise barrier is placed closer than 5 m from the traveled way,
Traffic Operations should be consulted early in the design. Signs ( overhead
and ground mounted) and other poles and standards for lighting,
Transportation Management items, call boxes, etc. should be detailed for
mounting on the wall, incorporated into the wall foundation and possibly
recessed into the surface of the wall.
( 2) Sight Distance Requirements. The stopping sight distance is of prime
importance for noise barriers located on the edge of shoulder along the
inside of a curve. Horizontal clearances, which reduce the stopping sight
distance should be avoided. Noise barriers within gore areas should begin or
end at least 60 m from the theoretical curb nose location.
( 3) Ultimate Location. Noise barriers should be constructed at the ultimate
location for the facility as discussed in the Project Development Procedures
Manual.
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1102.3 Noise Barrier Heights
( 1) Minimum Height. Noise barriers should have a minimum height of 1.8 m
( measured from the top of the barrier to the top of the foundation).
( 2) Maximum Height. Noise barriers should not exceed 4.3 m in height
( measured from the pavement surface at the face of the safety- shape barrier)
when located 4.5 m or less from the edge of the traveled way, and should
not exceed 5.0 m in height above the ground line when located more than
4.5 m from the traveled way.
( 3) Truck Exhaust Intercept. Current FHWA noise barrier design procedures
result in noise barrier heights, which often do not intercept noise, emitted
from the exhaust stack of trucks. For design purposes, the noise barrier
should intercept the line of sight from the exhaust stack of a truck to the
receptor. The truck stack height is assumed to be 3.5 m above the
pavement. The receptor is assumed to be 1.5 m above the ground and
located 1.5 m from the living unit nearest the roadway. If this location is not
representative of potential outdoor activities, then another appropriate
location should be justified in the noise study report.
( 4) Two- story Development. The noise barrier should not be designed to
shield the second story of two- story residences unless it provides
attenuation for a substantial number of residences at a reasonable increase
in cost. If the noise barrier is extended in height to provide second story
attenuation, this attenuation is to be at least 5 decibels.
( 5) Parallel Noise Barriers. Frequently, noise barriers are constructed to
shield noise receivers on both sides of a highway. These are referred to as
parallel barriers. If the barrier surfaces are hard, relatively smooth, and non
porous, such as concrete or masonry surfaces, the barriers can reflect noise
back and forth between the barriers, decreasing their effectiveness. As a
result of research performed by Caltrans and others, reflective parallel
barriers should have a width- to- height ratio ( W: H) of at least 10: 1 to avoid a
risk of perceptible reduction in performance of both noise barriers. The
width is the distance between the two barriers, and the height is the average
height of both barriers with reference to the roadway elevation. For example,
two parallel barriers, one 3 m the other 4 m high, should be separated by at
least 35 m to avoid a noticeable degradation in performance. A perceptible,
or noticeable decrease in performance is defined as a reduction of 3 dBA or
more in barrier attenuation.
1102.4 Noise Barrier Length
( 1) General. Careful attention should be given to the length of a noise barrier to
assure that it provides adequate attenuation for the end dwelling. The Caltrans
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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Environmental Handbook provides guidance on determining how far beyond
the end dwelling a noise barrier should be extended. When
appropriate, consideration should be given to terminating the noise barrier
with a section of the barrier perpendicular to the freeway. This could reduce
the overall barrier length, but may require an easement or acquisition from the
property owner to permit construction of the noise barrier off the right of way.
( 2) Gap Closures. In some cases, short gaps may exist between areas qualifying
for a noise barrier. The closure of these gaps should be considered on a project
by project basis and be justified in the Project Report.
( 3) Local Street Connections. At on- and off- ramp connections to local streets,
the Department's responsibility for noise abatement should be limited to areas
where the traffic noise level from the State highway is the predominant noise
source.
( 4) Barrier Overlaps. When the noise barrier has overlapping sections, such as
when concealing an access opening, the walls must be overlapped a minimum
of 2.5 to 3 times the offset distance in order to maintain the integrity of the
sound attenuation.
1102.5 Alternative Noise Barrier Designs
( 1) General. Every noise barrier that is constructed as a part of new highway
construction or reconstruction, or along freeways as a part of the Community
and School Noise Abatement Programs, requires at least two alternative
designs included in the contract plans. Selection of the most cost- effective and
aesthetically pleasing designs should include an analysis of their life- cycle
costs. The Traffic Noise Analysis Protocol discusses cost analysis of noise
barriers.
Standard sheets for noise barriers ( sound walls) developed by the Office of
Structure Design have been furnished to the Districts. These standard designs
include the following materials:
· Masonry block.
· Precast concrete panel ( with post or mounted on safety shaped barrier).
· Wood ( post and plank or framed plywood).
· Metal ( ribbed steel).
· Composite beam ( Styrofoam and wire mesh core with stucco exterior).
· Other design alternatives may be considered provided they meet the
structural and noise attenuation criteria. Questions regarding the
approval status of various designs or products should be directed to the
Headquarters Noise Abatement Design Standards Engineer in the Office
of Project Planning and Design.
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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Project Files for each noise barrier project should include the justification and
background for the design type or the options allowed on each project.
( 2) Design Procedures. The plans for alternative noise barriers are to be
prepared using the standard sound wall sheets and the appropriate Standard
Special Provisions. As a minimum, the sound wall plans are to show the
horizontal alignment, the wall profile made up of a top elevation line and a
bottom elevation line, the applicable standard sound wall detail sheets, and
aesthetic features sheet. The top elevation line is defined as the profile line of
the minimum wall height required for the design insertion loss, and the bottom
elevation line is defined as the finished grade ground line. If a concrete safety-shape
barrier is involved, the top of barrier is to be designated as the bottom
elevation line of the sound wall. For alternative sound walls not on a barrier,
the footing design does not have to be detailed on the plans. If a barrier is
required, the pile layout should be detailed for only one of the alternative
designs. Although this method does not require the detailing of one complete
sound wall alternative, it does not remove the necessity to solve drainage,
utility, foundation, or any other problems, which are unique to each project.
( 3) Pay Quantities. The pay item for alternative sound walls without a barrier is
square meter of sound wall and is measured between the top elevation line and
the bottom elevation line. The square meter cost includes all types of supports
( footings, piles and pile caps).
If the sound wall is on a barrier the sound wall pay item is measured from top
elevation line to top of barrier, and the supporting piles or footings and barrier
will be separate pay items.
The aesthetic features affect the amount of footing for the masonry block
design, and these features must be shown clearly on the plans. The " Typical
Sections" sheet is the recommended location to show the aesthetic treatment.
Refer to the Standard Special Provisions for more information on measurement
and pay quantities.
( 4) Shop Plans. The Special Provisions should require the successful bidder to
submit two sets of shop plans of the selected alternate for approval. These shop
drawings must show pile spacing, pile lengths, expansion joints location, and
aesthetic treatment.
( 5) Preliminary Site Data. In using the " Top Line/ Bottom Line" concept, it is
important that the preliminary site data be as complete as possible. To
eliminate or minimize construction change orders the following guidelines are
suggested.
· Provide accurate ground line profiles.
· Select only approved design alternative sound wall types.
· Provide adequate foundation investigation.
· Locate overhead and underground utilities.
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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October, 1998
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· Review drainage and show any modifications on the plans.
· Determine and specify architectural treatment.
· Determine the need for special design, and coordinate with the Office of
Structures Design during the early stages of design.
1102.6 Noise Barrier Aesthetics
( 1) General. A landscaped earth berm or a combination wall and berm tend to
minimize the apparent noise barrier height and are probably the most
aesthetically acceptable alternative, but unfortunately these alternatives are
not suitable for many sites due to limited space.
Some moderate additional cost to enhance the noise barrier's aesthetic quality
is usually warranted. However, elaborate or costly individualized designs,
which significantly increase the cost of the noise barrier should be avoided.
Sound walls should not be designed with abrupt beginnings or ends. Generally,
the ends of the sound wall should be tapered or stepped if the height of the
sound wall exceeds 2 m. The District Landscape Architect should be consulted
regarding the design of tapers or stepped ends, aesthetic treatment and
landscaping for noise barriers.
( 2) Standard Aesthetic Treatment. Only the standard aesthetic treatments for
the various alternative materials developed by the Division of Structures
should be used. A description of the different types of aesthetic treatments
developed is included in the " Instructions for Using the Standard Aesthetics
Features Sheets" which are available from the Aesthetics and Models unit of
the Division of Structures.
( 3) Nonstandard Aesthetic Treatment. When a nonstandard aesthetic treatment
is proposed for noise barriers, the Headquarters Traffic Liaison should be
consulted.
( 4) Planting of Noise Barriers. The use of plants in conjunction with noise
barriers can help to combat graffiti and enhance public acceptance of the noise
barrier. When landscaping is to be placed adjacent to the sound wall that will
eventually screen a substantial portion of the wall, only a minimal aesthetic
treatment is justified.
Index 902.3 of this manual and the Traffic Noise Analysis Protocol contain
additional information on the planting of noise barriers.
1102.7 Maintenance Consideration in Noise Barrier Design
( 1) General. Noise barriers placed within the area between the shoulder and
right of way line complicate the ongoing maintenance operations. When there is
a substantial distance behind the noise barriers and in front of the right of way
line, special consideration is required. If the adjoining land is occupied with
streets, roads, parks, or other large parcels, an effort should be made during
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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the right of way negotiations to have the abutting property owners maintain the
area. In this case, the chain link fence at the right of way line would not be
required. Maintenance by others may not be practical if a number of small
individual properties abut the noise barrier.
( 2) Access Requirements. Access to the backside of the noise barrier must be
provided if the area is to be maintained by Caltrans. In subdivided areas,
access can be via local streets, when available. If access is not available via
local streets, access gates or openings are essential at intervals along the noise
barrier. Access may be provided via offsets in the barrier. Offset barriers must
be overlapped a minimum of 2.5 to 3 times the offset distance in order to
maintain the integrity of the sound attenuation of the main barrier. Location of
the access openings must be coordinated with the District maintenance office.
( 3) Noise Barrier Material. The alternative materials selected for the noise
barrier should be appropriate for the environment in which it is placed. For
walls that are located at or near the edge of shoulder, the portion of the noise
barrier located above the safety- shape concrete barrier should be capable of
withstanding the force of an occasional vehicle, which may ride up above the
top of the safety barrier. At this location, concrete block, cast- in- place concrete,
or precast concrete panels are the recommended alternative sound wall
materials. In locations, which are susceptible to fires, use of wood noise
barriers should be avoided.
1102.8 Emergency Access Considerations in Noise Barrier Design
( 1) General. In addition to access gates being constructed in noise barriers to
satisfy the Department's maintenance needs, they may also be constructed to
provide a means to access the freeway in the event of a catastrophic event
which makes the freeway impassable for emergency vehicles. These gates are
not intended to be used as an alternate means of emergency access to adjacent
neighborhoods. Access to those areas should be planned and provided for from
local streets and roads. Small openings may also be provided in the noise
barrier, which would allow a fire hose to be passed through it. Local emergency
response agencies should be contacted early in the design process to determine
the need for emergency access gates and fire hose openings.
( 2) Emergency Access Gate Requirements. Access gates in noise barriers should
be kept to a minimum and should be at least 300 m apart. Locations of access
should be coordinated with the District Maintenance office. Only one opening
should be provided at locations where there is a need for access openings to
serve both the emergency response agency and Caltrans maintenance. Design
of gates should comply with the sound wall details developed by the Office of
Structures Design.
( 3) Fire Hose Access Openings. When there is no other means of providing fire
protection to the freeway, small openings for fire hoses may be provided. Fire
hose access should be located as close as possible to the fire hydrants on the
local street system. Where possible, fire hose access should be combined with
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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October, 1998
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emergency or maintenance access openings. Design of fire hose openings
should be requested from the Office of Structures Design.
1102.9 Drainage Openings in Noise Barrier
Drainage through noise barriers is sometimes required for various site
conditions. Depending on the size and spacing, small, unshielded openings at
ground level can be provided in the barriers to allow drainage and not defeat
the noise attenuation of the barrier. The following sizes of unshielded openings
at ground level are allowed for this purpose:
( a) Openings of 200 mm x 200 mm or smaller, if the openings are spaced at
least 3 m on center.
( b) Openings of 200 mm x 400 mm or smaller, if the openings are spaced at
least 6 m on center, and the noise receiver is at least 3 m from the nearest
opening.
The location and size of drainage openings need to be designed based on the
hydraulics of the area. The designer should also take into consideration
possible erosion problems that may occur at the drainage openings.
Where drainage requirements dictate openings that do not conform to the
above limitations, shielding of the opening will be necessary to uphold the
noise attenuation of the barrier. Shield design must consider the hydraulic
characteristics of the site. When shields are determined to be necessary,
consultation with the District Hydraulics Unit and the OPPD Coordinator and
Environmental Engineering staff is recommended.
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX A
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TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
October, 1998
B- 1
APPENDIX B – SUGGESTED WORKSHEETS, AND EXAMPLES OF
CALCULATING REASONABLE ALLOWANCES PER
RESIDENCE
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
October, 1998
B- 2
WORKSHEET “ A” FOR CALCULATING
REASONABLE ALLOWANCE PER RESIDENCE
PROJECT: Co. Rte. PM.
EA:
PROJECT LOCATION: Page of
NOISE BARRIER I. D. & LOCATION:
PROJECT ENGINEER: Date:
Base Allowance ( 1998 Dollars)
Update for year 2____
$ 15,000
_____
1) Absolute Noise Levels ( Choose One) Check
69 dBA or less: Add $ 2,000
70- 74 dBA: Add $ 4,000
75- 78 dBA: Add $ 6,000
More than 78 dBA: Add $ 8,000
2) “ Build” VS Existing Noise Levels ( Choose
One)
Check
Less than 3 dBA: Add $ 0
3- 7 dBA: Add $ 2,000
8- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
3) Achievable Noise Reduction ( Choose One) Check
Less than 6 dBA: Add $ 0
6- 8 dBA: Add $ 2,000
9- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
4) Either New Construction Or Pre- date 1978?
( Choose Yes or No)
Check
YES on either one: Add $ 10,000
NO on both: Add $ 0
Unmodified Reasonable Allowance Per Residence
Continued on Worksheet B
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
October, 1998
B- 3
WORKSHEET “ B” FOR CALCULATING REASONABLE ALLOWANCE
PER RESIDENCE
PROJECT: Co. : ______ Rte: ______ PM: _________
EA:
PROJECT ENGINEER:
PROJECT DESCRIPTION AND LOCATION:
____________________________________________
Page ___ of ___
Date: _________
NOISE
BARRIER I. D.
( From
Worksheet A)
REASONABLE
ALLOWANCE
PER
BENEFITED
RESIDENCE, Ai
( Worksheet A)
( a)
NO. OF
BENEFITTED
RESIDENCES
Ni
( b)
REASONABLE
ALLOWANCE
PER NOISE
BARRIER
( Ai x Ni)
( c)
( c = a x b)
FRACTION OF
TOTAL
REASONABLE
ALLOWANCE
( Ai x Ni)/ AT
( d)
( d = c/ box 1)
REDUCTION OF
REASONABLE
ALLOWANCE
PER NOISE
BARRIER
( e)
( e = d x box 3)
REDUCTION OF
REASONABLE
ALLOWANCE
PER
BENEFITED
RESIDENCE
( f)
( f = e/ b)
MODIFIED
REASONABLE
ALLOWANCE
PER
BENEFITED
RESIDENCE
( Ami )
( g)
( g = a – f)
TOTAL REASONABLE ALLOWANCE FOR
ABATEMENT ( AT)
( Box1)
ESTIMATED PROJECT COST x 0.5 ( Box2)
SUBTRACT BOX 2 FROM BOX 1
· If result is zero or less, STOP. Use the
reasonable allowances per residence in
column ( a) above.
· If result is greater than zero, the amount is
TOTAL ALLOWANCE EXCESS ( ET); continue
with columns ( d) through ( g).
( Box3)
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
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B- 4
** EXAMPLE**
WORKSHEET “ A” FOR CALCULATING
REASONABLE ALLOWANCE PER RESIDENCE
PROJECT: Sim- 999- 9.9
EA: 654321
PROJECT LOCATION:
Between Gilster Street & Jones Avenue
Page 1 of 4
NOISE BARRIER I. D. & LOCATION: SW- 1
PROJECT ENGINEER: Hendriks Date: 10/ 20/ 98
Base Allowance ( 1998 Dollars)
Update for year 2____ $ 15,000
_____
1) Absolute Noise Levels ( Choose One) Check
69 dBA or less: Add $ 2,000
70- 74 dBA: Add $ 4,000
75- 78 dBA: Add $ 6,000 4 $ 6,000
More than 78 dBA: Add $ 8,000
2) “ Build” VS Existing Noise Levels ( Choose
One)
Check
Less than 3 dBA: Add $ 0 4 $ 0
3- 7 dBA: Add $ 2,000
8- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
3) Achievable Noise Reduction ( Choose One) Check
Less than 6 dBA: Add $ 0
6- 8 dBA: Add $ 2,000 4 $ 2,000
9- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
4) Either New Construction Or Pre- date 1978?
( Choose Yes or No)
Check
YES on either one: Add $ 10,000 4 $ 10,000
NO on both: Add $ 0
Unmodified Reasonable Allowance Per Residence $ 33,000
Continued on Worksheet B
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
October, 1998
B- 5
** EXAMPLE**
WORKSHEET “ A” FOR CALCULATING
REASONABLE ALLOWANCE PER RESIDENCE
PROJECT: SIM- 999- 10.4
EA: 654321
PROJECT LOCATION:
Between Gilster Street & Jones Avenue
Page 2 of 4
NOISE BARRIER I. D. & LOCATION: SW- 2
PROJECT ENGINEER: Hendriks Date: 10/ 20/ 98
Base Allowance ( 1998 Dollars)
Update for year 2____
$ 15,000
_____
1) Absolute Noise Levels ( Choose One) Check
69 dBA or less: Add $ 2,000
70- 74 dBA: Add $ 4,000 4 $ 4,000
75- 78 dBA: Add $ 6,000
More than 78 dBA: Add $ 8,000
2) “ Build” VS Existing Noise Levels ( Choose
One)
Check
Less than 3 dBA: Add $ 0 4 $ 0
3- 7 dBA: Add $ 2,000
8- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
3) Achievable Noise Reduction ( Choose One) Check
Less than 6 dBA: Add $ 0
6- 8 dBA: Add $ 2,000 4 $ 2,000
9- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
4) Either New Construction Or Pre- date 1978?
( Choose Yes or No)
Check
YES on either one: Add $ 10,000
NO on both: Add $ 0 4 $ 0
Unmodified Reasonable Allowance Per Residence $ 21,000
Continued on Worksheet B
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
October, 1998
B- 7
** EXAMPLE**
WORKSHEET “ A” FOR CALCULATING
REASONABLE ALLOWANCE PER RESIDENCE
PROJECT: Sim- 999- 11.2
EA: 654321
PROJECT LOCATION:
Between Gilster Street & Jones Avenue
Page 3 of 4
NOISE BARRIER I. D. & LOCATION: SW- 3
PROJECT ENGINEER: Hendriks Date: 10/ 20/ 98
Base Allowance ( 1998 Dollars)
Update for year 2____
$ 15,000
_____
1) Absolute Noise Levels ( Choose One) Check
69 dBA or less: Add $ 2,000
70- 74 dBA: Add $ 4,000
75- 78 dBA: Add $ 6,000
More than 78 dBA: Add $ 8,000 4 $ 8,000
2) “ Build” VS Existing Noise Levels ( Choose
One)
Check
Less than 3 dBA: Add $ 0 4 $ 0
3- 7 dBA: Add $ 2,000
8- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
3) Achievable Noise Reduction ( Choose One) Check
Less than 6 dBA: Add $ 0
6- 8 dBA: Add $ 2,000 4 $ 2,000
9- 11 dBA: Add $ 4,000
12 dBA or more: Add $ 6,000
4) Either New Construction Or Pre- date 1978?
( Choose Yes or No)
Check
YES on either one: Add $ 10,000 4 $ 10,000
NO on both: Add $ 0
Unmodified Reasonable Allowance Per Residence $ 35,000
Continued on Worksheet B
TRAFFIC NOISE ANALYSIS PROTOCOL – APPENDIX B
For New Highway Construction and Highway Reconstruction Projects
October, 1998
B- 7
** EXAMPLE**
WORKSHEET “ B” FOR CALCULATING REASONABLE ALLOWANCE PER
RESIDENCE
PROJECT: Co. : Sim Rte: 999 PM: 9.5/ 12.0
EA: 654321
PROJECT ENGINEER: Hendriks
PROJECT DESCRIPTION AND LOCATION:
Outside widening between Gilster Street & Jones Avenue
Page 4 of 4
Date: 10/ 20/ 98
NOISE
BARRIER
I. D. ( From
Worksheet
A)
REASONABLE
ALLOWANCE
PER
BENEFITED
RESIDENCE,
Ai
( Worksheet A)
( a)
NO. OF
BENEFITTED
RESIDENCES
Ni
( b)
REASONABLE
ALLOWANCE
PER NOISE
BARRIER
( Ai x Ni)
( c)
( c = a x b)
FRACTION OF
TOTAL
REASONABLE
ALLOWANCE
( Ai x Ni)/ AT
( d)
( d = c/ box 1)
REDUCTION OF
REASONABLE
ALLOWANCE
PER NOISE
BARRIER
( e)
( e = d x box 3)
REDUCTION OF
REASONABLE
ALLOWANCE
PER
BENEFITED
RESIDENCE
( f)
( f = e/ b)
MODIFIED
REASONABLE
ALLOWANCE
PER
BENEFITED
RESIDENCE
( Ami )
( g)
( g = a – f)
SW- 1 $ 33,000 23 $ 759,000 0.341 $ 112,189 $ 4,878 $ 28,122
SW- 2 $ 21,000 15 $ 315,000 0.141 $ 46,389 $ 3,093 $ 17,907
SW- 3 $ 35,000 33 $ 1,155,000 0.518 $ 170,422 $ 5164 $ 29,836
TOTAL REASONABLE ALLOWANCE FOR
ABATEMENT ( AT)
( Box1) $
2,229,000
ESTIMATED PROJECT COST x 0.5 ( Box2) $
1,900,000
SUBTRACT BOX 2 FROM BOX 1
· If result is zero or less, STOP. Use the
reasonable allowances per residence in
column ( a) above.
· If result is greater than zero, the amount
is TOTAL ALLOWANCE EXCESS ( ET);
continue with columns ( d) through ( g).
( Box3) $
329,000