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

Barrier Elevation

The ground elevation of the area between a noise source and receiver affects the height of the noise barrier needed.  In the example at the right, Wall A must exceed the height of the noise source to break the noise path to the receiver.  Wall B, located at a higher ground elevation, can be much shorter to achieve the same noise reduction as Wall A.

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