This webpage provides information about traffic noise, noise barriers, the NYS Thruway Authority’s Noise Abatement Program and noise compatible land use planning.

Principles of Traffic Noise

Some important characteristics of traffic noise are:

• Noise:
  Noise is unwanted sound, and is perceived differently by each person.
• Intensity:
  Noise is sound pressure. Intensity is the sound pressure level, measured in units of decibels (dBA). See Figure 1 for examples of decibel levels from various sources.
• Loudest hour noise level:
  Traffic noise measurements and calculations are quantified for the loudest hour of the day. This normally corresponds with either the morning or evening heaviest traffic hour.

Basic Principles

• To the human ear, a 3 decibel change in sound pressure level is barely perceptible, and a 5 decibel change in sound pressure level is readily perceptible.
• In terms of sound intensity, a 10 decibel reduction in sound pressure level is half as loud. A 10 decibel increase in sound pressure level is twice as loud.
• A doubling of traffic volume increases sound pressure levels by 3 decibels.
• Dense vegetation must be greater than 100 feet thick and be high enough to completely block the line of sight to provide any noise reduction.
• When a noise barrier is constructed, the increase in sound pressure level on the opposite side of the highway, due to reflected noise, is generally not perceptible.

Noise Barriers

How Noise Barriers Work

Noise barriers are the most common abatement measure. They are solid obstructions built
between highways and residential neighborhoods. Before noise barriers are constructed, the incoming noise travels in a straight path between the source and receiver (see Figure 2). Noise barriers reflect a portion of the incoming noise. They also break the line of sight and diffract a portion of the incoming noise, causing it to take a longer path between the source and the receiver, resulting in a greater noise reduction (see Figure 3).

Three types of noise barriers are commonly constructed along the New York State Thruway:

• Earth Berms;
• Walls made of concrete, or composite
  material; and
• Walls constructed on top of an earth berm.

Noise Barrier Design

A noise barrier that just breaks the line of sight between a receiver and source provides a 5 decibel reduction. Noise barriers are designed to provide 10 decibels or greater noise reductions (7 decibels minimum) to the closest row of residences. It is very difficult to provide 15 decibel reductions in most locations, and nearly impossible to provide 20 decibel reductions. Noise barriers do not eliminate noise. Noise barriers, regardless of height, can only provide perceptible noise reductions within distances of 400 feet of the barrier. Noise barriers are most effective when located either near the noise source or near the receiver, and are more effective in reducing higher frequency tire/pavement noise than lower frequency truck engine and exhaust noise. Noise barriers are typically 15 to 20 feet high.

New York State Thruway Authority’s Noise Abatement Program

The New York State Thruway Authority follows the Federal Procedure for Abatement of Highway Traffic Noise and Construction Noise (23 CFR 772), the New York State Noise Analysis Policy and the NYS Thruway Authority Noise Policy to mitigate highway noise for two types of projects.

For New Road Construction- Type I Projects

Type I projects are mandatory based on regulations. Type I projects add one or more through travel lanes, construct a new road, or include a significant horizontal or vertical realignment of an existing highway. By definition, traffic noise impacts in residential areas with frequent outdoor use occur when the predicted future (within 20 years) loudest hour noise level equals or exceeds 66 dBA or is 6 decibels or more above the corresponding existing noise level. Where an impact is identified, noise abatement measures are recommended if all of the following conditions are met:

• 10 decibel or greater noise reductions (7 decibel minimum) can be attained, with 10 decibels desired for the closest receivers; and
• The abatement measures are reasonable, from a cost perspective, and feasible, from an engineering perspective; and
• The residents impacted by the traffic noise concur with the noise abatement recommendation.

For Existing Highways- Type II Projects

Type II projects provide noise abatement along existing highways and are voluntary. State highway agencies may elect to provide Type II noise abatement at their discretion, but noise barriers must compete for funding with other necessary transportation improvements.

Beginning in January 1998, the Thruway Authority funded a Type II Noise Abatement Program with the goals of providing relief to previously studied communities on a prioritized basis, and undertaking a comprehensive study of locations where noise impacts may exist but are yet unquantified.

In May 2004, the Thruway Authority completed a Thruway-wide Noise Barrier Prioritization Study that provides an objective determination of where to construct noise barriers in priority order as Thruway Authority monies become available. The prioritization method calculates a priority index based on the number of affected people, the noise levels presently experienced, the decrease in noise levels with the noise barrier, and the cost of the barrier construction.

To qualify for this program, the residential development had to:

• Be located along portions of the Thruway where the Thruway Authority has maintenance, operation, and capital improvement responsibilities; and
• To be given first (Tier 1) priority; include 25 or more residential structures that were constructed prior to 1976, located within 200 feet of the nearest Thruway edge of pavement; or
• To be given second (Tier 2) priority; include 25 or more residential structures that were constructed between 1976 and 1998, located within 200 feet of the nearest Thruway edge of pavement.

The Thruway Authority intends to provide noise abatement as established by the study as monies become available. The development of noise reduction projects will be undertaken in partnership with benefiting communities.

Noise Compatible Local Land Use Planning

The Diagram to the right shows how open space buffers can minimize noise impacts on residential development.

Why is local land use planning needed?

Consistent with federal policy, the NYS Thruway Authority Type II Noise Abatement Program will not provide noise abatement for residential construction that occurred after 1998. The Thruway Authority is encouraging noise compatible land use planning to reduce noise impacts to future residential and other noise sensitive development near the Thruway. Noise compatible land use planning improves community character, quality of life and can increase property values.

For more information on noise compatible local land use planning, see the Federal Highway Administration (FHWA) guides:

www.fhwa.dot.gov/environment/noise/quietzon/index.htm

www.fhwa.dot.gov/environment/audible/index.htm

The Diagram to the right displays how less noise sensitive commercial development can be placed next to highways, with residences farther away.

How is it implemented?

Local governments can use one or more of the following approaches to encourage noise compatible land use planning in their communities:

• Planning, zoning or other legal means (e.g. subdivision or development standards, building codes, or occupancy permits).
• Municipal controls that include land or easement purchases or the acceptance of land donations.
• Community education to inform citizens, developers and local planners (e.g. indicate areas of noise impact on municipal maps).
• Acoustical site planning, architectural design and acoustical construction (e.g. sound insulation, acoustical windows, building orientation, and/or earth berms).

For more information, contact:

Phone number: 1 (877) 901-2700 Ext 2983
Email by using our on-line form.