HomeMy WebLinkAbout02-21-2008 Planning and Zoning Commission
PLANNING AND ZONING COMMISSION
Thursday, February 21, 2008 - 5:15 PM
Work Session
Iowa City City Hall
Emma J. Harvat Hall
220 S. Gilbert Street
AGENDA:
A. Call to Order
B. Discussion of draft Subdivision Regulations
C. Adjournment
Informal
Formal
City of Iowa City
MEMORANDUM
Date: February 15,2008
To: Planning and Zoning Commission
From: Karen Howard, Associate Planner
RE: Draft subdivision code
At your meeting on Thursday we suggest that we continue to review the subdivision code
section by section. We will keep track of those issues for which you would like more
information or which you would like to have a more in depth discussion. So far, the list of
discussion topics includes:
· Connectivity standards
· Highway noise buffer requirements
· Lot size requirements for double- and triple-fronting lots
· State Urban Design Standards and ADA standards for sidewalks
Several of you specifically requested information regarding noise buffer standards along 1-80
and Highway 218. Although we may not reach that point in the draft in our discussion on
Thursday, I've attached several excerpts from longer documents related to noise measurement
techniques and standards established by the federal government for your review. Also
included is a copy of the standards adopted by the City of Madison. When we get to the
point in the draft when we are discussing the highway noise buffer requirements we will
bring a map of the areas in Iowa City that would be affected. Let me know if you would like
to have a copy of the longer documents from which these excerpts were taken.
Ron Knoche, City Engineer, has agreed to attend a future meeting to answer questions that
you might have related to public works standards. We will keep of list of your questions for
Ron as we proceed through this initial review of the document.
The Noise
Guidebook
A Reference Document for
Implementing the Department of
Housing and Urban Development's
Noise Policy
Prepared By The Environmental
Planning Division,
Office of Environment and Energy
//(
/
The Dynamics of the Noise Problem
There are basically two types of noise
problems'. There Is the specific, job
related, occupational noise problem
created by extremely loud machinery.
Then there Is the community noise
problem where the combined effect of
many Individual noise sources
creates an overall noise level that Is
unacceptable. In the following pages
we will be addressing the community
noise problem only.
The main contributors to a
community noise problem are
transportation sources such as
highways, railroads and airports.
These sources are the most pervasive
and continuing ofthe noise sources
within the community. Of course, at
any given site, there may be other
noise sources which add to the
problem, sources such as
jackhammers at a construction site.
But in general, and for the purposes of
this section, the main concern Is with
the transportation sources.
The dynamics of a noise problem
are based on the relationship between
the noise source, the person or place
exposed to the noise (hereafter called
the receiver) and the path the noise
will travel from source to receiver.
The source generates a given
amount of noise which travels along
the path and arrives at the receiver.
The amount of noise will be reduced
to some extent as a result of how long
that path Is or whether there are any
barriers along the path. The severity
of the impact on the receiver Is a
function of what type of activity is
taking place, whether It Is Indoors or
outdoors, and what type of building It
Is in If the activity Is Indoors. Figure 3
contains some basic compatibility
guidelines.
The Impact of the noise can be
altered or mitigated by changing the
characteristics of any of the three
elements: source, path or receiver.
Later on we will look at the various
mitigation measures that are
possible. Our concern however will be
primarily with the receiver and the
path. Control of the sources
themselves Is the specific
responsibility of agencies such as the
Environmental Protection Agency
(EPA) or the Federal Aviation
Administration (FAA).
Figure 2
Dynamics of a HoI.. Problem
o 0
)
Source
Path
Receiver
Figure 3
Land u.. Compatibility Guidelines
LAND USE CATEGORY
Residential - Single Family, Duplex, Mobile Homes
Residential - Multiple Family, Dormitories, etc.
Transient Lodging
School Classrooms, Libraries, Churches
Hospitals, Nursing Homes
Auditoriums, Concert Halls, Music Shells
Sports Arena, Outdoor Spectato,r Sports
Playgrounds, Neighborhood Parks
GolI Courses, Riding Stables, Water Rec., Cemeteries
Olflce Buildings, Personal, Buslne.s and Professional
Commercial - Retail, Movie Theaters" Restaurants
Commercial - Wholesale, Some Retails, Ind., Mfg., UtII.
Manufacturing, Communication (Noise Sensitive)
Livestock Farming, Animal Breeding
Agriculture (except livestock), Mining, Fishing
Public Rlght.of.Way
Extensive Natural Recreation Areas
OLdn = NEF Value + 35
o
B'........
.....,..............
~
Clearly
Acceptable
Normally
Acceptable
:-:.:.:.:
.........
Clearly
Unacceptable
2
')
LAND USE INTERPRETATION
FOR NEF VALUE'
20 30 40 50
65 75 85
Ldn VALUES
Normally
Unacceptable
-r---
The ideal solution to a potential
problem is to reduce the noise being
produced by the source. The best
solution available to HUD, or the
community, however, Is to make sure
that noise sensitive uses are located
where they will not be exposed to high
noise levels. The next best approach
to mitigating noise Impact Is to
attempt to reduce the amount of
noise that reaches the receiver. This
can be accomplished through the use
of barriers such a.s walls or earthen
berms, or combinations of both, along
the noise path. If the use of barriers Is
not possible then the only alternative
available is to provide noise reduction
measures In any structures
associated with the activity so that at
least the Interior spaces are not
exposed to high noise levels. This
approach is considered the least
desirable because most of the land
uses we are concerned about, such as
residential, do have outdoor areas and
activities associated with them which
would remain exposed to high noise
levels.
A Note on Descriptors
A key factor in the growth of our
ability to evaluate and reduce noise
impacts has been the development of
better tools to measure and describe
the noise levels generated by various
sources. The development of better
tools (called noise descriptors or
metrics) has been particularly
Important for dealing with community
noise problems. Many of the older
descriptor systems could only be
used for one or two sources such as
cars and railroads, but not airplanes.
Since the community noise problem
very often includes noise from all
these sources the lack of an adequate
descriptor made it difficult to do an
adequate evaluation.
The most advanced descriptor
currently in general use is the day
night average sound level system,
abbreviated as DNL and symbolized
mathematically as ldn. The day night
average sound level is the 24 hour
average sound level, expressed in
decibels, obtained after the addition
of a 10 decibel penalty for sound
levels which occur at night between
10 PM and 7 AM. This nighttime
penalty is based on the fact that many
studies have shown that people are
much more disturbed by noise at
night than at any other time. This is
not unusual in that background noise
is often much less at night and also
people tend to be doing very noise
sensitive things at night, such as
trying to sleep.
Another feature of the DNL system
that Is very Important Is that It can be
used to describe noise from all
sources. Thus, using the DNL system,
we can describe the total noise
exposure at a site, something many
other descriptor systems couldn't do.
The DNL system has been adopted
by the EPA, the Department of
Defense (000) and HUD, and more
recently by the FAA, specifically for
describing environmental Impacts for
airport actions. We expect that very
soon it will be in almost universal use
In the U.S.
Issues
The main issues involved In any noise
analysis can be summarized briefly.
. How much noise Is a site exposed
to
. What types of activities are being
affected and how severely
. Is it reasonable to redesign the site
to relocate noise sensitive activities
. And, if not, how much protection
can be provided through various
attenuation measures.
Your approach to these Issues will
be affected In many ways by the
location of the project In question.
Projects in suburban or rural areas
can be approached differently
because the available mitigation
options are greater and often the
noise exposure Itself is not so severe.
In urban situations, however, the
noise exposure is often more severe
but at the same time the options for
mitigation or resltlng are more
limited. In the urban setting Innovative
design and the use of advanced
attenuation measures becomes
critical. Fortunately our experience
has shown that good design and
construction can relieve or
substantially reduce major noise
problems.
3
Legal Provisions
General Legislation and Background
The Federal legislation which
addresses noise Issues is somewhat
different from other environmental
legislation. The Clean Air Act, for
example, required the Environmental
Protection Agency to set up actual
mandatory standards for air quality
which were supposed to be met by all
jurisdictions. EPA even has the
authority to take punitive steps
against cities which are not making
"reasonable further progress"
towards achieving these air quality
goals. There Is no similar legislation
that covers noise. The approach has
been to tackle the noise problem at
the source by controlling the amount
of noise that can be emitted by the
Individual airplane engine or the
individual jackhammer. Agencies like
HUD or the Farmers Home
Administration have developed '
regulations which are related to the
overall community noise level, but
they only affect their own programs
and are not binding on local
communities. The Veterans
Administration program only relates
to aircraft noise and also only affects
Its own programs.
The major pieces of Federal
legislation related to noise include:
The Noise Control Act of
1972 directed EPA to promote an
environment for all Americans free
from noise that jeopardizes their
health and welfare. It also included a
requirement for EPA to set a criterion
for noise level adequate to protect
health and welfare with an adequate
margin of safety but without regard to
cost or feasibility.
Quiet Communities Act of
1978 amended The Noise Control Act
of 1972 to encourage noise control
programs at the State and community
level.
Federal Aid Highway Act of
1970 established the requirement
that noise controi be a part of the
planning and design of all federally
aided highways.
Aviation Safety and Noise
Abatement Act of 1979 requires FAA
to develOp a single system for
measuring noise at airports and under
certain conditions to prepare and
publish noise maps.
_:-~,!,j7~
t
Evaluation of Impact
HUD Regulations set forth the
following exterior noise standards for
new housing construction assisted or
supported by the Department:
65l.-cjn or less - Acceptable
Exceeding 65l.-cjn but not exceeding
75 l.-cjn - Normally
Unacceptable - appropriate sound
attenuation measures must be
provided: 5 decibels attenuation
above the attenuation provided by
standard construction required In 65
l.-cjn to 70 l.-cjn zone; 10 decibels
additional attenuation In 70 l.-cjn to 75
l.-cjn zone.
Exceeding 75l.-cjn - Unacceptable
HUD's regulations do not contain
standards for Interior noise levels.
Rather a goal of 45 decibels Is set
forth and the attenuation
requirements are geared towards
achieving that goal. It Is assumed that
with standard construction any
building will provide sufficient
attenuation so that if the exterior level
Is 65l.-cjn or less, the Interior level will
be 45l.-cjn or less.
Once you have determined the '
overall noise exposure for the site you
compare It to the above standards. If
the overall site exposure is 65l.-cjn or
less the project is acceptable. If the
exposure is between 65 l.-cjn and 75
l.-cjn you should consider alternative
locations or providing adequate
attenuation with the first preference,
as we've noted, being for the
construction of some kind of barrier
to prevent noise from reaching the
site. If providing adequate attenuation
is Impossible or Impractical then the
project should be considered
unacceptable.
Suggested MItigation
General Considerations
As discussed briefly earlier, there are
three basic approaches for mitigating
the high noise exposures. The first
and best Is to relocate noise sensitive
uses out of the high noise area. The
second Is to prevent noise from
reaching the noise sensitive user
through some sort of barrier. And the
third, and least desirable approach, Is
to provide attenuation for at least the
Interiors of any buildings located In
the high noise areas.
Specific Considerations
Relocating Noise Sensitive Use.
By far the most desirable mitigation
approach Is to relocate noise
sensitive uses out of the high noise
area although. If the site Is large
enough It may be possible to locate
non-noise sensitive uses between the
source and the sensitive use, for
example a parking lot might be
located between a road and a park
(see Figure 5). The workcharts In the
Noise Assessment Guidelines can be
used In reverse to tell you exactly how
far away from the noise source you
need to be.
When sites are small,very dense or
when the source affects the entire
site It Is very difficult to mitigate by
changing the site plan. Then the next
option must be considered: erecting
some type of barrier between the
source and the receiver.
Figure 5
The Audible
Landscape
In cluster development, open space can be
placed near the highway to reduce noise
Impacts on residences
B.rrI....
Barriers are most effective for at or
below ground level sources. They
have no effect on noise from aircraft
overflights and are limited In practical
application with elevated sources
such as elevated trains. The key to the
effectiveness of a barrier Is whether
or not It breaks the line of sight
between the source and the receiver.
If a barrier does not completely break
the line of sight either because It Is
not high enough, or not long enough
then Its effectiveness is greatly
reduced.
Barriers can be actual walls,
earthen mounds (called berms) or
even other buildings. The use of other
non-noise sensitive buildings as
barriers Is a particularly good
approach In that It need not add to the
cost of the project and may not create
the aesthetic problem a large wall
might create (see Figure 6).
Highway
~,
A
Figure 8
The Audible
Llndacape
Placement of noise compatible land uses
near highway In Planned Unit D~velopment
Figure 7
The Audible
Llndscape
Use of acoustical architectural design to
reduce noise impacts on more noise
sensitive living spaces
Bedroom Bedroom L1vl ng Room
. I;:::;:;:;:::;:::; 1{):~{rtI:j:~:jrrJ
.....]
::;::::::::: ~ - ili~
I
Den ~ Bath ilt.:.:::~:::.~:... Dining Room
Highway
-- ---- ---- -- - - - - ------ ------
7
As pointed out earlier, the
effectiveness of a barrier Is
determined In large part by Its height
and length. Some studies have shown
that the effectiveness of a barrier can
be reduced by as much as 50% If it
Isn't long enough. Again, the Noise
Assessment Guidelines contain
procedures for determining the
effectiveness of barriers.
Incorporating Noise Attenuation
Measures Into the Building
If neither relocation or barriers Is a
reasonable noise attenuation option,
the last resort is to Incorporate noise
attenuation measures into the
buildings themselves. This Is not
considered the best solution because
It leaves the outdoor areas, some of
which may be for quiet recreation,
exposed to high noise levels. But If
development must take place and
barrler~.are Impossible, then the
noise attenuation measures should
be employed In building design and
construction.
Without going into great technical
detail, noise attenuation construction
measures generally fall into four
categories.
(1) Reducing the total area of
windows or other acoustically weaker
building elements
(2) Sealing off "leaks" around
windows, doors, vents.
(3) Improving the actual sound
attenuating properties of small
building elements such as windows,
doors, etc.
(4) Improving the actual sound
attenuating properties of major
building elements such as roof and
wall construction.
In addition, noise attenuation in
buildings can be provided by
designing interior spaces so that
"dead" spaces such as closets or
corridors act as buffer zones (see
Figure 7). And finally noise
attenuation can be provided by
reducing the need for open windows
by providing air conditioning.
Many of the steps that would be
taken to provide noise attenuation
also help conserve energy. Good
weatherstripping around windows
and doors is one example. Another
might be reducing window areas in
walls if the noise source is to the
north or west. Because many of these
measures serve two purposes, they
should not necessarily be considered
a burdensome requirement but rather
just good design and construction.
HIGHWAY TRAFFIC NOISE ANALYSIS
AND ABATEMENT POLICY AND
GUIDANCE
by
u.s. Department of Transportation
Federal Highway Administration
Office of Environment and Planning
Noise and Air Quality Branch
Washington, D.C.
June 1995
INTRODUCTION
Studies have shown that some of the most pervasive sources of noise in our environment today are those associated
with transportation. Traffic noise tends to be a dominant noise source in our urban as well as rural environment. In
response to the problems associated with traffic noise, the United States Code of Federal Regulations Part 772
(23 CFR 772), "Procedures for Abatement of Highway Traffic Noise and Construction Noise," establishes
standards for mitigating highway traffic noise.
The purpose of this document is to provide Federal Highway Administration (FHW A) policies and guidance for the
analysis and abatement of highway traffic noise. A 3Y:z-day training course, sponsored by the National Highway
Institute, is available for instructing FHW A field and State highway agency (SHA) staffs in the details ofthe
policies and the technical procedures required for analyzing and abating traffic noise impacts.
LEGISLATION
Effective control of the undesirable effects of highway traffic noise requires that (I) land use near highways be
controlled, (2) vehicles themselves be quieted, and (3) mitigation of noise be undertaken on individual
highway projects.
The first component is traditionally an area of local responsibility. The other components are the joint responsibility
of private industry and of Federal, State, and local governments.
Land Use Planning and Control
The Federal Government has essentially no authority to regulate land use planning or the land development process.
The FHW A and other Federal agencies encourage State and local governments to practice land use planning and
control in the vicinity of highways. The FHW A advocates that local governments use their power to regulate land
development in such a way that noise-sensitive land uses are either prohibited from being located adjacent to a
highway, or that the developments are planned, designed, and constructed in such a way that noise impacts are
minimized.
Some State and local governments have enacted legislative statutes for land use planning and control. As an
example, the State of California has legislation on highway noise and compatible land use development. This State
legislation requires local governments to consider the adverse environmental effects of noise in their land .
development process. In addition, the law gives local governments broad powers to pass ordinances relating to the
use ofland, including among other things, the location, size, and use of buildings and open space. Wisconsin has a
State law which requires formal adoption of a local resolution supporting the construction of a proposed noise
barrier and documenting the existence of local land use controls to prevent the future need for noise barriers
adjacent to freeways and expressways.
Although some other States and local governments have similar laws, the entire issue of land use is extremely
complicated with a vast array of competing considerations entering into any actual land use control decisions. For
this reason, it is nearly impossible to measure the progress of using land use to control the effects of noise.
1
Source Control
The Noise Control Act of 1972 gives the Federal Environmental Protection Agency (EP A) the authority to establish
noise regulations to control major sources of noise, including transportation vehicles and construction equipment.
In addition, this legislation requires EPA to issue noise emission standards for motor vehicles used in Interstate
commerce (vehicles used to transport commodities across State boundaries) and requires the FHW A Office of
Motor Carrier Safety (OMCS) to enforce these noise emission standards. .
The EP A has established regulations which set emission level standards for newly manufactured medium and heavy
trucks that have a gross vehicle weight rating (OVWR) of more than 4,525 kilograms and are capable of operating
on a highway or street. Table 1 shows the maximum noise emission levels allowed by the EPA noise regulations for
these vehicles.
Table 1: Maximum Noise Emission Levels as Required by EPA for Newly Manufactured Trucks
with GVWR Over 4,525 Kilograms
Effective Date January 1, 1988
Maximum Noise Level 15 Meters from Centerline of Travel 80 dBA
Using the Society of Automotive Engineers, Inc. (SAE), test
procedure for acceleration under 56 kph
For existing (in-use) medium and heavy trucks with a OVWR of more than 4,525 kilograms, the Federal
government has authority to regulate the noise emission levels only for those that are engaged in interstate
commerce. Regulation of all other in-use vehicles must be done by State or local governments. The EPA emission
level standards for in-use medium and heavy trucks engaged in interstate commerce are shown in Table 2 and are
enforced by the FHW A OMCS.
Table 2: Maximum Noise Emission Levels as Required by EPA for In-Use Medium and Heavy Trucks
with GVWR Over 4,525 Kilograms Engaged in Interstate Commerce
Effective Date Speed Maximum Noise Level 15 Meters from Centerline of Travel
January 8, 1986 < 56 kph 83 dBA
January 8, 1986 > 56 kph 87 dBA
January 8, 1986 Stationary 85 dBA
Highway Project Noise Mitigation
The National Environmental Policy Act (NEPA) of 1969 provides broad authority and responsibility for evaluating
and mitigating adverse environmental effects including highway traffic noise. The NEP A directs the Federal
government to use all practical means and measures to promote the general welfare and foster a healthy
environment.
A more important Federal legislation which specifically involves abatement of highway traffic noise is the
Federal-Aid Highway Act of 1970. This law mandates FHW A to develop noise standards for mitigating highway
traffic noise.
2
The law requires promulgation oftraffic noise-level criteria for various land use activities. The law further provides
that FHW A not approve the plans and specifications for a federally aided highway project unless the project
includes adequate noise a.batement measures to comply with the standards. The FHW A has developed and
implemented regulations for the mitigation of highway traffic noise in federally-aided highway projects.
The FHW A regulations for mitigation of highway traffic noise in the planning and design of federally aided
highways are contained in 23 CFR 772. The regulations require the following during the planning and design of a
highway project: (1) identification oftraffic noise impacts; (2) examination of potential mitigation measures; (3)
the incorporation of reasonable and feasible noise mitigation measures into the highway project; and (4)
coordination with local officials to provide helpful information on compatible land use planning and control. The
regulations contain noise abatement criteria which represent the upper limit of acceptable highway traffic noise for
different types of land uses and human activities. The regulations do not require that the abatement criteria be met
in every instance. Rather, they require that every reasonable and feasible effort be made to provide noise mitigation
when the criteria are approached or exceeded. Compliance with the noise regulations is a prerequisite for the
granting of Federal-aid highway funds for construction or reconstruction ofa highway.
NOISE FUNDAMENTALS
As we all know, sound is created when an object moves; the rustling of leaves as the wind blows, the air passing
through our vocal chords, the almost invisible movement of the speakers on a stereo. The movements cause
vibrations of the molecules in air to move in waves like ripples on water. When the vibrations reach our ears, we
hear what we call sound.
Noise is defined as unwanted sound. Sound is produced by the vibration of sound pressure waves in the air. Sound
pressure levels are used to measure the intensity of sound and are described in terms of decibels. The decibel (dB)
is a logarithmic unit which expresses the ratio of the sound pressure level being measured to a standard reference
level. Sound is composed of various frequencies, but the human ear does not respond to all frequencies.
Frequencies to which the human ear does not respond must be filtered out when measuring highway noise levels.
Sound-level meters are usually equipped with weighting circuits which filter out selected frequencies. It has been
found that the A-scale on a sound-level meter best approximates the frequency response of the human ear. Sound
pressure levels measured on the A-scale of a sound meter are abbreviated dBA.
In addition to noise varying in frequency, noise intensity fluctuates with time. In the past few years, there has been
a definite trend toward the use of the equivalent (energy-average) sound level as the descriptor of environmental
noise in the U.S. The equivalent sound level is the steady- state, A-weighted sound level which contains the same
amount of acoustic energy as the actual time-varying, A-weighted sound level over a specified period of time. If the
time period is I hour, the descriptor is the hourly equivalent sound level, Leq(h), which is widely used by SHAs as a
descriptor oftraffic noise. An additional descriptor, which is sometimes used, is the LIO' This is simply the
A-weighted sound level that is exceeded 10 percent of the time.
A few general relationships may be helpful at this time in understanding sound generation and propagation. First, as
already mentioned above, decibels are logarithmic units. Consequently, sound levels cannot be added by ordinary
arithmetic means. A chart for decibel addition is shown in Table 1. From this table it can be seen that the sound
pressure level from two equal sources is 3 dB greater than the sound pressure level of just one source. Therefore,
two trucks producing 90 dB each will combine to produce 93 dB, not 180 dB. In other words, a doubling of the
noise source produces only a 3 dB increase in the sound pressure level. Studies have shown that this increase is
barely detectable by the human ear.
3
Table 3: Decibel Changes, Loudness, and Energy Loss
Sound Level Relative Loudness Acoustic Energy Loss
Change
OdBA Reference 0
-3 dBA Barely Perceptible Change 50%
-5 dBA Readily Perceptible Change 67%
-10 dBA Half as Loud 90%
-20 dBA 1/4 as Loud 99%
-30 dBA 1/8 as Loud 99.9%
Table 4: Rules for Combining SQund Levels by "Decibel Addition"
For noise levels known or desired to an accuracy or :tl decibel (acceptable for traffic noise
analyses):
When two decibel values differ by Add the following amount to the higher value
OorldB 3 dB
20r3dB 2 dB
4t09dB 1 dB
10 dB or more o dB
Secondly, an increase or decrease of 10 dB in the sound pressure level will be perceived by an observer to be a
doubling or halving of the sound. For example, a sound at 70 dB will sound twice as loud as a sound at 60 dB.
Finally, sound intensity decreases in proportion with the square of the distance from the source. Generally, sound
levels for a point source will decrease by 6 dBA for each doubling of distance. Sound levels for a highway line
source vary differently with distance, because sound pressure waves are propagated all along the line and overlap at
the point of measurement. A long, closely spaced continuous line of vehicles along a roadway becomes a line
source and produces a 3 dBA decrease in sound level for each doubling of distance. However, experimental
evidence has shown that where sound from a highway propagates close to "soft" ground (e.g., plowed farmland,
grass, crops, etc.), the most suitable dropoffrate to use is not 3 dBA but rather 4.5 dBA per distance doubling. This
4.5 dBA dropoffrate is usually used in traffic noise analyses.
For the purpose of highway traffic noise analyses, motor vehicles fall into one of three categories: (I) automobiles -
vehicles with two axles and four wheels, (2) medium trucks - vehicles with two axles and six wheels, and (3) heavy
trucks - vehicles with three or more axles. The emission levels of all three vehicle types increase as a function of
the logarithm of their speed.
4
The level of highway traffic noise depends on three things: (I) the volume of the traffic, (2) the speed of the traffic,
and (3) the number of trucks in the flow of the traffic. Generally, the loudness of traffic noise is increased by
heavier traffic volumes, higher speeds, and greater numbers of trucks. Vehicle noise is a combination of the noises
produced by the engine, exhaust, and tires. The loudness of traffic noise can also be increased by defective mufflers
or other faulty equipment on vehicles. Any condition (such as a steep incline) that causes heavy laboring of motor
vehicle engines will also increase traffic noise levels. In addition, there are other, more complicated factors that
affect the loudness oftraffic noise. For example, as a person moves away from a highway, traffic noise levels are
reduced by distance, terrain, vegetation, and natural and manmade obstacles. Traffic noise is not usually a serious
problem for people who live more than 150 meters from heavily traveled freeways or more than 30 to 60 meters
from lightly traveled roads.
FHWA NOISE REGULATIONS
The current FHW A procedures for highway traffic noise analysis and abatement are contained in 23 CFR 772,
"Procedures for Abatement of Highway Traffic Noise and Construction Noise." These procedures specifY the
requirements that SHAs must meet when using Federal-aid funds for highway projects.
This discussion will address those requirements and point out the most important issues related to the requirements.
Each paragraph of23 CFR 772 will be presented in boldface type and followed by a discussion of that paragraph.
Some parts are self-explanatory and need only a sentence or two of discussion . Other, more complicated paragraphs
will have greater discussion.
772.1: PURPOSE. To provide procedures for noise studies and noise abatement measures to help
protect the public health and welfare, to supply noise abatement criteria, and to establish
requirements for information to be given to local officials for use in the planning and design of
highways approved pursuant to Title 23, United States Code (U.S.c.).
The protection of the public's health and welfare is an important responsibility that FHW A helps to accomplish
during the planning and design ofa highway project. The U.S. Congress has directed that this be done when the
1970 Federal-Aid Highway Act was passed. Concerned citizens and States encouraged Congress to provide this
protection.
772.3: NOISE STANDARDS. The highway traffic noise prediction requirements, noise analyses,
noise abatement criteria, and requirements for informing local officials in this directive
constitute the noise standards mandated by 23 U.S.C. 109(i). All highway projects which are
developed in conformance with this directive shall be deemed to be in conformance with the
Federal Highway Administration (FHW A) noise standards.
This paragraph makes the whole 23 CFR 772 the FHW A noise standard. The standard is required by 23 US.C.
109(i). Some people mistake the noise abatement criteria for the FHW A standard. Early on, FHW A did not want to
be restricted to specific noise levels that may not be achieved in most highway projects. So, a standard was
developed that would best serve the public in terms of protection and reasonable cost.
772.5: DEFINITIONS
a. Desil!:n Year - the future year used to estimate the probable traffic volume for which a
highway is designed. A time, 10 to 20 years, from the start of construction is usually
used.
5
b. Existinl! Noise Levels - the noise, resulting from the natural and mechanical
sources and human activity, considered to be usually present in a particular
area.
c. ~10 - the sound level that is exceeded 10 percent of the time (the 90th percentile)
for the period under consideration.
d. ~10i!!2 - the hourly value of LJO'
e. 1.q - the equivalent steady-state sound level which in a stated period of time
contains the same acoustic energy as a time-varying sound level during the same
period.
f. 1.qi!!} - the hourly value of Leq.
g. Traffic Noise Impacts - impacts which occur when the predicted traffic noise
levels approach or exceed the noise abatement criteria (Table 5), or when the
predicted traffic noise levels substantially exceed the existing noise levels.
h. Tvpe I Proiects - a proposed Federal or Federal-aid highway project for the
construction of a highway on new location or the physical alteration of an
existing highway which significantly changes either the horizontal or vertical
alignment or increases the number of thtough-traffic lanes.
i. Tvpe II Proiects - a proposed Federal or Federal-aid highway for noise
abatement on an existing highway.
Most of these definitions are self-explanatory. However, the definition for "Traffic Noise Impacts" warrants further
attention. A traffic noise impact occurs when the predicted levels approach or exceed the noise abatement criteria
(NAC) or when predicted traffic noise levels substantiallv exceed the existing noise level, even though the predicted
levels may not exceed the NAC. This definition reflects the FHW A position that traffic noise impacts can occur
under either of two separate conditions: (1) when noise levels are unacceptably high (absolute level); or (2) when a
proposed highway project will substantially increase the existing noise environment (substantial increase). In order
to adequately assess the noise impact ofa proposed project, both criteria must be analyzed. While the FHWA noise
regulations do not define "approach or exceed, all SHAs must establ1sh a definition of "approach" that is at least 1
dBA less than the NAC for use in identifYing traffic noise impacts in traffic noise analyses.
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Table 5: Noise Abatement Criteria (NAC)
Hourly A-Weighted Sound Level in Decibels (dBA)*
Activity Leq(h) Lw(h) Description of Activity Category
Category
A 57 60 Lands on which serenity and quiet are of extraordinary significance
(Exterior) (Exterior) 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 70 Picnic areas, recreation areas, playgrounds, active sports areas,
(Exterior) (Exterior) parks, residences, motels, hotels, schools, churches, libraries, and
hospitals.
C 72 75 Developed lands, properties, or activities not included in Categories
(Exterior) (Exterior) A or B above.
D -- -- Undeveloped lands.
E 52 55 Residences, motels, hotels, public meeting rooms, schools,
(Interior) (Interior) churches, libraries, hospitals, and auditoriums.
*
Either Leq(h) or Lw(h) (but not both) may be used on a project.
NOTE:
These sound levels are only to be used to determine impact. These are the absolute levels where
abatement must be considered. Noise abatement should be designed to achieve a substantial noise
reduction - not the noise abatement criteria.
In developing the NAC contained in the noise regulations, the FHW A attempted to strike a balance between that
which is most desirable and that which is feasible. Factors such as technical feasibility, the unique characteristics of
highway-generated noise, cost, overalI public interest, and other agency objectives were important elements in the
process of setting a standard. Establishing values for the NAC was approached by attempting to balance the control
of future increases in highway noise levels and the economic, physical, and aesthetic considerations related to noise
abatement measures. Numerous approaches were considered in establishing the criteria, including (I) hearing
impairment, (2) annoyance, sleep, and task interference or disturbance, and (3) interference with speech
communication. The first deals in terms of very loud noises seldom encountered for a highway project beyond the
roadway proper. The second approach was desirable in principle but was insufficiently researched to be useful in
practice. However, the third approach - speech interference - was usefulIy applied to the problem of highway traffic
noise. Thus, it should be remembered that the NAC are based upon noise levels associated with interference of
speech communication and that the NAC are a compromise between noise levels that are desirable and those that are
achievable. FHW A believes that our regulations provide a welI-balanced approach to the problem of
highway-traffic-generated noise.
The NAC are not magical numbers. Traffic noise impacts can occur below the NAC. The NAC should not be
viewed as Federal standards or desirable noise levels; they should not be used as design goals for noise barrier
construction. AII of the regulations contained in 23 CFR 772 constitute the standards mandated by the Federal-Aid
Highway Act of 1970. Noise abatement should be designed to achieve a substantial noise reduction, which SHAs
have defined in practice to be in the range of 5-1 0 dBA. The NAC should onlv be used as absolute values which,
when approached or exceeded, require the consideration of traffic noise abatement measures.
The 23 CFR 772 purposefully provides the SHAs with flexibility to establish their own definition of "substantial
increase." A 10 dBA increase in noise levels is a doubling of the perceived loudness. A 15 dBA increase in noise
levels represents more than a doubling of the loudness. Factors such as available resources, the public's attitudes
7
toward highway traffic noise, and the absolute noise levels may influence a State's definition. The FHW A will
accept a well-reasoned definition that is uniformly and consistently applied. Several SHA definitions have evolved
and are shown in Table 6.
T bl 6 C't . U d b St t t D fi "s b t f I"
a e : rJ erJa se 'Y a es 0 e me u s an la
Increase (dB) Subjective Descriptor
Criteria 1 0-5 Little increase
5-15 Some increase
>15 Substantial increase
Criteria 2 <10 Little increase
>10 Substantial increase
Criteria 3 0-5 No increase
5-10 Minor increase
10-15 Moderate increase
>15 Substantial increase
The use of subjective descriptors to describe traffic noise impacts is not required. Traffic noise impacts occur based
upon the definition contained in 23 CFR 772. This definition does not contain subjective descriptors. Ifimpacts
are identified, noise abatement measures must be considered and implemented if found to be reasonable and
feasible. When analyzing the reasonableness of abatement, SHAs should consider the relationship between the
absolute noise levels and the extent of the increase over existing noise levels for a given situation. A small increase
at a higher absolute level (e.g., 70 dBA to 75 dB A) can be more important and justifY greater consideration than a
similar increase at a lower absolute level (e.g, 50 dBA to 55 dBA). Likewise, a large increase at a lower absolute
level (e.g., 40 dBA to 55 dBA) can be less important and justifY less consideration than a similar increase at a
higher absolute level (e.g., 55 dBA to 70 dBA).
772.7: APPLICABILITY:
a. Tvpe I Proiects. This directive applies to all Type I projects unless it is specifically
indicated that a section applies only to Type II projects.
b. Tvpe II Proiects. The development and implementation of Type II projects are
not mandatory requirements of
23 U.S.C. l09(i) and are, therefore, not required by this directive. When Type II
projects are proposed for Federal-aid highway participation at the option of the
highway agency, the provisions of paragraphs 6, 8, and 11 of this directive shall
apply.
The regulation applies to all Type I and Type II projects. The implementation ofa Type II program is optional and
not mandatory.
8
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From Madison, WI municipal code
other adopted Master Plan elements,
including the Peripheral Area Development
Plan. The permanent open space lands
shall be accessible and open for use by the
general public. The open space lands shall
be exclusive from, and in addition to, lands
required for dedication to comply with
applicable public parks and open space
dedication requirements and shall be
provided at a ratio of two acres of
permanent open space lands for every one
acre of developed lands, including street
rights of way. For the purpose of this
provision, wetlands, flood plain lands,
steep slopes, or other lands which are not
developable because of sensitive
environmental features shall not be
counted as permanent open space lands in
calculating the ratio of permanent open
space lands provided versus developed
lands. Steep slopes shall include lands
which have grades of twenty percent (20%)
or more.
(d) Highway Noise Land Use
1. General
a. No owner of any unplatted lands which is
adjacent to any existing state or federal
expressway or freeway and for which a preliminary
plat approval was not granted prior to November 6,
1990, shall be granted final plat approval or shall
commence or cause to be commenced
construction of any structure, unless approved by
the Director of the Department of Planning and
Development or her/his designee.
b. Prior to approval of any preliminary plat, final
plat or commencement of construction of any
structure, every application for approval shall be
submitted in writing to the Department of Planning
and Development by the owner of the land on
which the structure is proposed to be constructed
and shall contain the following information:
i. Identification of the land on which the
construction is proposed;
ii. The section under which approval is
requested;
iii. Information and data supporting the
claim that the appropriate requirements
shall be met including specific
enumerations that the Wisconsin
Department of Transportation's
Administrative Code TRANS 405 and the
. Federal Highway Administration's
Procedures for Abatement of Highway
Traffic Noise and Construction Noise, Title
23, CFR, Chapter I, Subchapter J, Part
772, provisions shall be met and any other
information which the Department of
Planning and Development may require.
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iv. Approval certificate from the
Department of Transportation certifying
that hourly traffic sound levels Leq(h) as
hereinafter indicated, are within
permissible levels or that appropriate
sound attenuation measures are
incorporated into the design and
construction of any structures to satisfy the
highway noise provisions within this
ordinance.
c. In addition to the requirements contained in
subparagraph b. above, the application shall also
contain the following information as well as any
other information requested by the Director of
Transportation bearing on the approval:
i. The existing maximum hourly traffic
sound level, Leq(h), for a representative
sample of locations, measured in
accordance with guidelines presented in
"Sound Procedures for Measuring Highway
Noise: Final Report", August 1981, U.S.
Department of Transportation, Federal
Highway Administration, Arlington, VA, or
modeled according to a methodology
consistent with the methodology in the
FHWA Highway Traffic Noise Prediction
Model (Report No. FHWA-RD-77-108);
ii. The projected future Leq(h) at the site
resulting from future traffic increases; and
Hi. Where applicable, plans for sound
attenuation measures on the site and/or of
the structure proposed to be built and the
amount of sound attenuation anticipated as
a result of these measures.
2. Construction Restrictions for Habitable and
Institutional Structures.
a. No new single family residential structure shall
be approved for construction if any exterior hourly
traffic sound level Leq(h) anywhere within a
proposed outdoor living area is projected to be
equal to or in excess of 67 dBA upon completion of
the structure or anytime thereafter.
b. No new multiple-family residence, dormitory,
mobile home park, transient lodging, school,
hospital, nursing home or similar structure, or
substantial modification of such existing structure,
shall be approved for construction if any exterior
hourly traffic sound level, Leq(h), anywhere within a
proposed outdoor living area on the site is
projected to be equal to or in excess of 67 dBA
upon completion of the structure or modification or
anytime thereafter.
c. Construction otherwise prohibited shall be
allowed if there are no outdoor use areas on the
site of the proposed structure projected to be
exposed to an hourly traffic sound level, Leq(h),
equal to or in excess of 67 dBA and provided that
there is incorporated into the design and
~
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construction of the structure such sound
attenuation measures as are necessary to reduce
the maximum interior hourly traffic induced sound
level, Leq(h), in a habitable room to 52 dBA upon
completion of the structure or modification, or
anytime thereafter.
d. Prior to issuance of any building permit for any
structure regulated pursuant to Subparagraph c.
above, the owner of the structure shall submit to
the Transportation Department, plans and
specifications identifying the sound attenuation
measures to be incorporated into the design and
construction of the structure to meet the interior
Leq(h) criteria.
e. The Department of Transportation may
conduct such inspections and measurements as
are necessary to ensure the proper implementation
of the sound attenuation measures proposed
pursuant to Subparagraph d. above and to
ascertain compliance with this provision.
3. Recreational Area
a. No land shall be designated or approved for
construction or used as a public or private exterior
recreational area, including, but not limited to,
children's playgrounds, outdoor theaters and
amphitheaters, picnic grounds, tennis courts and
swimming pools, if any exterior hourly traffic sound
level, Leq(h), anywhere on the site of the proposed
recreational areas is projected to be equal
to or in excess of 67 dBA upon completion
of the construction or designation of the
site or anytime thereafter, except for the
following:
i. This section shall not apply to the
designation or approval of any green belt
or open space in any area in which the
noise level exceeds the level specified in
Subparagraph a. above regardless of
whether such green belt or open space is
open to public use, provided that no
recreational improvement or facility is
constructed thereon.
ii. Designation or approval of exterior
recreational area otherwise prohibited
under Subparagraph a. above shall be
allowed if the noise level specified in that
subparagraph can be achieved by
appropriate means of sound attenuation,
such as berms, barriers, or buildings, at the
perimeter of or elsewhere on the site.
b. No new interior recreational facility, including,
but not limited to, gymnasiums, ice or roller skating
rinks, indoor swimming pools, and tennis courts,
shall be approved for construction if the hourly
traffic sound level, Leq(h), anywhere on the site is
projected to be equal to or in excess of 67 dBA
upon completion of the structure or anytime
thereafter, unless there is incorporated into the
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design and construction of the structure such
sound attenuation measures as are necessary to
reduce the maximum hourly traffic induced sound
level, Leq(h), to 52 dBA.
(e) Remedies. Failure to comply with the requirements of this
section shall invalidate purported transfers of titles at the option of
the purchaser in accordance with provisions of Sec. 236.31(3) Wis.
Stats. Building permits shall also be refused for construction on
sites created in violation of these requirements.
(f) Exceptions. The provisions of this ordinance insofar as it may
apply to divisions of less than five (5) parcels, shall not apply to:
1. Transfers of interests in land by will or pursuant to
court order.
2. Leases for a term not to exceed ten (10) years,
mortgages or easements.
3. The sale or exchange of parcels of land between
owners of adjoining property if additional lots are not
thereby created and the lots resulting are not reduced
below the minimum sizes required by this ordinance, the
Zoning Code, or other applicable laws or ordinances.
4. Leases or transfers of lands within an approved
Planned Commercial Site.
5. Where Certified Survey Maps are prepared for
exempted land divisions as enumerated in paragraphs 1-4
above, the Secretary of the Plan Commission or her/his
designee, upon review, shall have the authority to sign an
appropriate notation thereon that the Certified Survey Map
is exempted from Plan Commission review pursuant to the
applicable provision. (Cr. by Ord. 10,588,2-12-93)
(g) Appeals to Circuit Court. Any person aggrieved by an
objection to a plat or land division, condition of plat or land division
approval or failure to approve a plat or land division may appeal
from such action on a plat by the Common Councilor from such
action on a land division by the Plan Commission acting under Sec.
16.23(3)(c) of the Madison General Ordinances, as provided in
62.23(7)(e)10 to 15, Wis. Stats., and authorized by Sec. 236.13(5),
Wis. Stats. within thirty (30) days of notification of such final action
by letter from the Secretary of the Plan Commission. (Am. by Ord.
10,981,9-14-94)
(Sec. 16.23(3) Am. by Ord. 10,560, Adopted 12-15-
(4) Summarized Procedure For Dividing Land Within The City Limits Or
Its Extraterritorial Area. In planning and developing a subdivision or land
division within the City of Madison or its extraterritorial area, the subdivider
or his agent shall in every case follow one of the following procedures:
(a) For ownerships of eighty (80) acres or
1. Pre-application conference, preliminary plat (entire
parcel) and final plat (all or part of preliminary plat); or
2. Pre-application conference, comprehensive
development plan (COP) on entire ownership, preliminary
plat (first final plat area) and final plat (all or part of
preliminary plat).
(b) For ownerships of less than eighty (80) acres with five (5) lots
or more to be platted in five (5) years or less:
Pre-application conference, preliminary plat (entire parcel),
final plat.
(c) For ownerships of less than eighty (80) acres with less than
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