Pennsylvania Statutes Title 75 Pa.C.S.A. Vehicles § 7743. Mufflers and sound control

(a) General rule.--It is unlawful to operate a snowmobile or an ATV which is not equipped at all times with a muffler in good working order which blends the exhaust sound into the overall snowmobile or ATV sound and is in constant operation to prevent excessive or unusual sound. The exhaust system shall not emit or produce a sharp popping or crackling sound. The sound intensity produced by a snowmobile shall not exceed 82dbA when measured in accordance with SAE Recommended Practice J 192 Exterior Sound Level for Snowmobiles, as amended. The department may by regulation adopt more stringent sound requirements for snowmobiles. The department shall by regulation adopt sound requirements for in-use operation of ATV's using measurement procedures in accordance with SAE Recommended Practice J 1287 July 1998, Measurement of Exhaust Level of Stationary Motorcycles. The sound level intensity produced by an ATV manufactured before January 1, 1998, shall not exceed 99dbA, or decibels, when measured at 20 inches. The sound level intensity produced by an ATV manufactured on or after January 1, 1998, shall not exceed 96dbA, or decibels, when measured at 20 inches.

(b) Modified mufflers prohibited.--It is unlawful to modify a muffler or to operate a snowmobile or an ATV with a modified muffler so as to increase the sound level of the snowmobile or ATV above the level allowed by this section.

(c) Exception.--This section does not apply to organized races or similar competitive events.