Ky.gov

Noise Barriers - Soundwalls

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The Kentucky Transportation Cabinet assesses noise impacts and proceeds with abatement only on active construction projects meeting specific environmental criteria. After construction is completed and the highway has been opened for public usage, federal funding is not available to retrofit existing conditions and construct noise barrier walls for mitigation of transportation noise along the highway. We are able to retrofit walls if there has been an addition of lanes for more capacity. 

In recent years, members of the legislature have put sections of new sound barriers in the State Highway Plan funded purely with state funds.  These projects are at the request of their constituents.  We suggest you contact your state representative and senator about this issue.


There are two ways that sound walls are considered by KYTC: 
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​​​​1. Federally funded roadway project that adds through lanes (capacity) to the roadway.  

Per the KYTC Noise Analysis and Abatement Policy, measurements are taken to identify a feasible and reasonable noise abatement measure for impacted receptors that approach or exceed the Noise Abatement Criteria specified in 23 CFR Part 772. ​

A noise barrier must meet both the feasibility and reasonableness criteria specified by KYTC to be proposed.  This type of project requires an in-depth environmental review process.

A noise barrier is considered feasible if it would provide a substantial noise reduction (5 dBA or more) for three or more impacted receptors and would not pose safety or maintenance problems.  The determination of reasonableness is based upon the noise reduction design goal (7 dBA or more for at least 50% of front row benefited receptors), cost-effectiveness (a cost per benefited receptor of $35,000 or less), and the desires of the benefitted receptors (via a public involvement process to be conducted during final design).

NOTE:  If no federally funded highway project is being planned or designed in your area, then KYTC cannot conduct a noise analysis. ​ 


2.  State-funded stand-alone projects that are identified by the General Assembly/Legislature. 

These sound walls are commonly referred to as a retro-fit project. It is for stand-alone noise walls where major reconstruction is not planned in the near future. KYTC project funding is appropriated through the legislatively enacted Highway Plan in a two-year budget cycle.  The Highway Plan is how the Kentucky General Assembly authorizes major highway improvement projects.  Sound wall/barrier pr​ojects can be identified and funded by the General Assembly as part of the biennial highway plan and do not require any reasonable or feasible analysis.  Historically, more projects are listed in the Highway Plan than funds available. We suggest you contact your state representative and senator about this issue.​

NOTE:  If no federally funded highway project is being planned or designed in your area, then KYTC cannot conduct a noise analysis. 


​Links
​Click here to hear different decibel levels and how they are affected by a sound​ wall.

KYTC Division of Environmental Analysis - Noise 

Frequently Asked Questions
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​FHWA Noise Barrier Analysis

KYTC District 5 Construction Projects​

​​What are Sound Walls / Noise Barriers? 
​Noise barriers are solid obstructions built between the highway and the homes along a highway. They do not completely block all noise — they *may* reduce overall noise levels. Effective noise barriers typically reduce noise levels by 5 to 10 decibels (dB), cutting the loudness of traffic noise by as much as one half. For example, a barrier that achieves a 10-dB reduction can reduce the sound level of a typical tractor trailer pass-by to that of an automobile.

Barriers can be formed from earth mounds or “berms" along the road, from high, vertical walls, or a combination of earth berms and walls. Earth berms have a very natural appearance and are usually attractive. They also reduce noise by approximately 3 dB more than vertical walls of the same height. However, earth berms can require a lot of land to construct, especially if they are very tall. Walls require less space but are usually limited to eight meters (25 feet) in height for structural and aesthetic reasons.
​How Does a Sound Wall /Noise Barrier Work?
​Noise barriers *may* reduce the sound that enters a community from a busy highway by either absorbing the sound, transmitting it, reflecting it back across the highway, or forcing it to take a longer path over and around the barrier.
A noise barrier must be tall enough and long enough to block the view of a highway from the area that is to be protected, the “receiver."
Noise barriers provide very little benefit for homes on a hillside overlooking a highway or for buildings that rise above the barrier. A noise barrier may achieve a 5 dB noise level reduction, when it is tall enough to break the line of sight from the highway to the home or receiver. After it breaks the line of sight, it can achieve approximately 1.5dB of additional noise level reduction for each meter of barrier height.




 



Engine compression brakes, or "jake brakes"​
Commercial vehicle drivers sometimes use engine compression brakes, or "jake brakes," to slow their vehicles down rather than using the normal braking systems. Manufacturers of engine compression brakes argue that these systems are a safety device because they make navigating downhill grades and mountainous terrain easier. KYTC understands the safety purpose of these braking systems but we also are sensitive to the noise related to the use of these braking systems.
 
KYTC has reviewed the legalities associated with the competing perspectives of safety and noise for these braking systems. This review revealed that ''jake brakes" are authorized to be on vehicles as long as the braking system complies with both state and federal laws pertaining to noise standards. The real problem stems from modified or defective exhaust systems that are in violation of state and federal laws that, in turn, result in the objectionable noise.
 
It has been determined that KYTC does not have the legal authority to restrict the use of ''jake brakes" as a safety device on commercial vehicles. On the other hand, local law enforcement and the Kentucky Commercial Vehicle Enforcement officers do have the authority to enforce improper equipment laws.

Therefore, KYTC does not install "No Jake Brake" signs but we do encourage you to contact law enforcement agencies of to promote existing commercial vehicle equipment laws.
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​KYTC District 5 Home Page​
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This page is maintained by KYTC District 5 Staff, who may be contacted to make corrections or changes.

​Page Last Updated: 09-20​-2023

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200 Mero St Frankfort, KY
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(502) 564-4890
Transportation.ky.gov

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