Vehicle Exhaust Noise

Illinois Vehicle Exhaust Noise Laws

Many car enthusiasts decide to modify their car’s exhaust system, but there are laws governing the noise limit your vehicle can produce. The section below outlines relevant laws and legislation pertaining to car exhaust noise laws in Illinois.

Illinois exhaust noise laws summary:

To summarize, any exhaust systems on vehicles registered in Illinois must not produce “excessive or unusual” noise. Aftermarket exhaust systems or any exhaust modifications must not in any way amplify or increase noise normally generated by vehicle’s original equipment.

Essentially this means many exhaust system modifications frequently done on sports or racing vehicles can be considered illegal. If you install aftermarket exhaust modifications make sure it does not produce excessive noise.

Illinois laws require passenger and other vehicles under 8,000 pounds in weight to emit no more than 76 DB A on highways where speed limit is under 35 miles per hour, or 85 DB A on highways with speed limit over 35 miles per hour.

The following law excerpt is from Illinois Vehicle Code, § 12.602.

 Sec. 12-602. Mufflers, prevention of noise.

Every motor vehicle driven or operated upon the highways of this State shall at all times be equipped with an adequate muffler or exhaust system in constant operation and properly maintained to prevent any excessive or unusual noise. No such muffler or exhaust system shall be equipped with a cutout, bypass or similar device. No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise of such vehicle above that emitted by the muffler originally installed on the vehicle, and such original muffler shall comply with all the requirements of this Section.

IL Administrative Code Section 902.120: Standards applicable to all passenger cars and to other motor vehicles

Passenger vehicles and other motor vehicles under 8,000 pounds in weight may produce up to 74 db A when speed limit is under 35 mph, or 82 db A where speed limit is over 35 mph (with 3% allowed variance). Most vehicles fall into this category.

Table below displays all vehicle exhaust noise level requirements as per Illinois Administrative Code:

Illinois vehicle noise limits:
Speed limit < 35 mph Speed limit > 35 mph
All vehicles under 8,000 pounds 74-76 dB A 82 – 85 dB A
All vehicles over 8,000 pounds 80 – 82 dB A 86 dB A
Motorcycles 86 dB A 90 dB A

“dB A” means the composite abbreviation for the A-weighted sound level and the unit of sound level, the decibel.

Illinois noise limit penalties:

Violating car noise limits in Illinois carries a $75 – $125 fine.

Sources and more info:

  1. Illinois Compiled Statutes: Vehicle Code, Chapter 12: Equipment of Vehicles, Article VI: Miscellaneous Requirements, Section 12-602: Mufflers, prevention of noise.
  2. Illinois Noise Related Statutes and Regulations (.pdf file; see or search for “Section 902.120”, “Section 902.121”, “Section 902.122”); or:
  3. Illinois Administrative Code, Title 35: Environmental Protection, Subtitle H: Noise, Chapter I: Pollution Control Board, Part 902: Sound Emission Standards and Limitations for Motor Vehicles, Subpart B.

Please remember that state laws are subject to change, and it is important to consult the current statutes and regulations in Illinois but also your local city or county to ensure accurate information.

This article about Illinois Vehicle Exhaust Noise Laws was last updated in 2024. If any of our information is incomplete or outdated please let us know. Thank you!