(625 ILCS 5/12-602) (from Ch. 95 1/2, par. 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.

(Source: P.A. 77-37.)