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Traffic Noise

IDOT Noise Policy and Analysis Requirements

It is the policy of the Illinois Department of Transportation (IDOT) to assess traffic noise impacts on proposed transportation projects such as highways on new location or the addition of through travel lanes. Land uses evaluated for noise impacts include residential areas, schools, libraries, and parks or other recreational areas which may be affected by highway traffic noise. During the project development stage traffic noise studies are performed. The Federal Highway Administrations’ (FHWA) Traffic Noise Model (TNM) is used to predict traffic noise impacts. If the predicted noise levels approach or exceed FHWA’s noise abatement criteria, noise abatement measures are considered. Abatement measures such as noise walls or berms are effective in reducing traffic noise that will result from the transportation improvement. While landscaping can be used as an effective visual barrier, studies have shown that trees and shrubbery alone do not provide significant reduction in noise levels and are not approved as a noise abatement measure.

IDOT’s Highway Traffic Noise Assessment Manual describes techniques and procedures for analyzing and reporting traffic noise impacts, and includes a discussion of abatement measures which can be incorporated into project designs to mitigate traffic noise impacts. This guidance manual is issued in an effort to ensure that studies and reports on traffic noise prepared by or for IDOT are consistent with existing laws and regulations and are technically accurate and sufficient.

For more information about the FHWA Highway Noise Program, please visit

Traffic Noise - Resources and Frequently Asked Questions (FAQ)

Residents, business owners, and community groups often have questions about traffic noise and the tools available to IDOT for managing the impacts of highway traffic noise near where people live, work, and play.  The IDOT environmental team has developed resources to aid in the understanding of the nature of noise in general, specific issues associated with highway traffic noise, and IDOT policies regarding traffic noise abatement.  Click on the links below to view resources including a four-part YouTube video series, informational handouts, a glossary of key terms, and a document of frequently asked questions (FAQ) related to highway traffic noise.

Traffic Noise Informational Videos

Other Resources for Understanding Traffic Noise