Subd. 1. It shall be unlawful for any person to discharge the exhaust or permit the discharge of the exhaust from any motor vehicle except through a muffler that effectively prevents abnormal or excessive noise and complies with all applicable state laws and regulations.
Subd. 2. It shall be unlawful for the operator of any truck to intentionally use an engine retarding brake on any public highway, street, parking lot, or alley within the city which causes abnormal or excessive noise from the engine because of an illegally modified or defective exhaust system, except in an emergency.