Illinois Department of Transportation, Ann L. Schneider, Secretary
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Part I Noise Fundamentals

Part II Noise Analysis

Part III Noise Abatement

Frequently Asked Questions

Glossary and Acronyms

Noise Source Abatement


Vehicle Noise Emission Standards

  • The Noise Control Act of 1972 initiated noise regulations.
  • The US Environmental Protection Agency (US EPA) gained authority to establish noise regulations for new vehicles and construction equipment.
  • US EPA established regulations only for new trucks with gross vehicle weight of more than 10,000 pounds.
  • IDOT has no control over vehicle noise emissions.

Pavement Material

  • At speeds greater than 30 mph, the dominant noise source for automobiles is tire interaction with pavement. Alternative pavement material and tire designs may reduce noise.
  • Pavement material is based on economic and engineering factors.
  • Opportunities to modify pavement material are generally limited and should not jeopardize safety.
  • Noise characteristics will change with time due to pavement wear.

Traffic Restrictions

  • Alternative truck routes limiting the use of certain roads or streets.
  • Interstate commerce (i.e., trucks) cannot be prohibited from using interstate highways.

Speed Limitations

  • Reduced speeds would reduce overall noise levels.
  • A 20-mile per hour decrease is needed for a  noticeable (5 dBA) decrease in noise.
  • Speed reductions decrease roadway capacity and increase congestion.
  • Posted speed limits are based on roadway design or speed studies.

Engine Braking Restrictions

  • Engine braking is also called air braking.
  • Engine braking is used by diesel truck drivers to slow down the vehicle.
  • Consists of a truck modification to use engine compression for braking power.
  • Sound it creates is a heavy thumping from the motor.
  • Areas can be signed to prohibit engine braking.
  • Due to occasional use of engine braking, prohibition will likely not reduce overall noise level.
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