City officials in Vancover, WA, voted unanimously last week to ban unmuffled compression brakes inside city limits. The ban fines truckers $250 for operating an engine brake without a muffler.

While all new vehicles are required to comply with Environmental Protection Agency noise regulations, city officials point out that older trucks and those modified by their drivers might not meet the noise standard.

Drivers accused of violating the proposed ordinance would be allowed to defend themselves by proving that the brakes were used during an emergency. The new ban exempts emergency vehicles.