Illinois Department of Transportation, Erica Borggren, Acting Secretary
Patrick J. Quinn, Governor
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Part I Noise Fundamentals

Part II Noise Analysis

Part III Noise Abatement

Frequently Asked Questions

Glossary and Acronyms

Noise Path Abatement

Noise Path Abatement Options

  • Construction of noise barrier
  • Noise walls, earth berms or a combination of the two.
  • Reduce traffic noise levels by lengthening the noise path between source and receiver.

Alteration of horizontal alignment

  • Changing roadway location or elevation to increase the noise path length between noise source and receiver to reduce noise levels.
  • Option available only for Type I projects

Alteration of vertical alignment

  • Alteration of the vertical alignment to take advantage of natural features to break line of sight between the noise source and receiver, similar to a noise barrier.

Effects of Vegetation

  • Vegetation can provide aesthetic value and psychological relief from traffic noise.
  • Vegetation is not used by FHWA or IDOT for traffic noise reduction because:

A. Vegetation would need to be at least 200 feet wide and 18 feet high to reduce noise levels by 10 dBA.

B. In most cases, available right-of-way cannot accommodate this width.

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