barrier What do noise process barriers look like?

At the start of a state project, the Here’s a sampling of noise barriers in Wisconsin Department of Transportation Wisconsin communities. (WisDOT) determines noise impacts and evaluates possible mitigation measures, such as noise barriers. Jay Waldschmidt, P.E. Environmental Process and After careful evaluation and a voting Documentation Section Chief process, WisDOT installs noise barriers WisDOT Central Office along portions of state highways to 4822 Madison Yards Way 5th Floor South minimize noise impacts. P.O. Box 7965 Madison, WI 53707-7965 Enclosed are frequently asked questions (608) 267-9806 about noise barriers and their answers. [email protected] This will help you understand WisDOT Noise Barriers: policy for installing noise barriers and how adjacent landowners and residents I-39/90/94 at Cottage Grove near Madison. What You are involved. Should Know wisconsindot.gov

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I-41 in Green Bay.

Noise barrier on residential side. Gray non-textured

Q. How does WisDOT determine • Or when predicted future Q. How effective are noise barriers? Q. Why does WisDOT build noise where to place noise barriers? levels exceed existing levels by 15 A. Effectiveness depends on the barriers? ® A. The Traffic Noise Model (TNM 2.5) (dB) or more. distance between the impacted receptor A. It is part of a federal requirement. is used to predict future traffic sound NLC is divided into land use categories and the barrier. For areas located U.S. (23 CFR 772) levels. Impacted locations are then that include residential areas, serene/quiet directly behind a barrier, providing an requires state highway agencies to considered for noise abatement lands, parks, schools, hotels, offices, etc. eight (8) dB reduction, the noise level will determine noise impacts and evaluate measures. Project staff be cut in half. This benefit decreases as possible mitigation measures as part of evaluates potential design a listener moves farther away from the a proposed Type I Federal Aid project. Q. What does reasonable and traffic control and feasible mean? barrier and is negligible at distances modifications, such as greater than 500 feet. Q. What is a Type I project? A. For a noise barrier to be prohibiting trucks or reasonable, the total cost A. Type I projects include: changing the horizontal or may not exceed $47,000 Q. How much do noise barriers cost? • The construction of a highway on a vertical alignment. Then, per benefited receptor. To A. Current construction costs average new location; noise barriers are be considered a benefit, $28 per square foot. The typical height • The physical alteration of an modeled for attenuating an impacted receptor must required for an eight (8) dB reduction is existing highway (that substantially noise and are optimized receive a minimum of eight 16 feet. With these figures, a barrier changes either the horizontal or the to ensure a beneficial and (8) dB . For would cost $2.2 million per mile per side vertical alignment); economical barrier is a noise abatement of road. • The addition of a through traffic designed. After the measure to be feasible, a lane(s) or auxiliary lane (that is not evaluation, a Madison Beltline (US 12/14) at Seminole Highway. minimum of one impacted Q. Who pays for noise barriers? a turn lane); determination is made area or common use area A. Federal and state highway money is • The addition or relocation of an whether each barrier is a reasonable must achieve a five (5) noise used for the construction of noise lane(s) or ramp(s) and feasible mitigation measure. reduction. barriers. added to a quadrant to complete an existing partial interchange; Q. What types of barriers are there? Q. Who is responsible for noise barrier Q. Does the public have any input? • Restriping existing pavement to add A. Noise barriers are typically made of maintenance? A. Yes. Noise barriers that are a through lane or the addition of a pre-cast, composite, sound-absorptive A. WisDOT is responsible for determined to be reasonable and new or substantial alteration of a panels that can have different texture maintenance. feasible must receive a vote of support weigh station, rest stop, ride-share looks and colors (i.e., stone, brick, from a simple majority of all votes cast lot or toll plaza. smooth or grooved patterns). Q How is the barrier height determined? by the adjacent landowners and A. Noise barriers are designed to provide a residents of the benefited areas. A public Q. What is an impacted receptor? minimum of eight (8) dB reduction in information meeting will be conducted in A. An impacted receptor/listener or average background traffic noise for the order to provide adjacent landowners common use area is one with: majority of residences located directly and residents of the benefited areas an • A predicted future traffic sound level behind the barrier and a nine (9) dB opportunity to ask questions and learn which approaches or exceeds the reduction for at least one impacted about the voting process. WisDOT Noise Level Criteria (NLC) location. Computer models determine the for Considering Barriers for different height of the barrier needed to provide

land use categories; noise reduction.

I-39/90/94 at Buckeye Road near Madison.