Rapid City, SD Noise Ordinances: Vehicle Noise (2026)

020, no one may operate a motor vehicle in the city unless its exhaust system is free from defects affecting sound reduction, equipped with a muffler or other noise-dissipative device, free of cutouts or bypasses, and not modified to amplify noise above what a factory muffler would emit. 030. 020, separately requires every motor vehicle to carry a muffler in good working order that prevents 'excessive raucous or unusually loud noise, smoke or flame,' and bars anyone from selling, installing or using a muffler cutout, bypass or Hollywood pipe, or any device that would ignite exhaust gases to produce flame.

120: the use of an unmuffled dynamic braking device (commonly called an air brake, engine brake, compression brake, Jacob's Brake or Jake Brake) is prohibited within the city, with an exception for City emergency vehicles whether or not responding to an emergency. A driver cited for using one can raise an affirmative defense only by proving, by a preponderance of the evidence, that the vehicle was being driven lawfully, the speed was reasonable under the circumstances, and the driver reasonably believed the unmuffled brake was necessary to avoid an imminent threat to safety or property. 24.