Ask a Trooper: What are rules for exhaust noise and mufflers?

Published 7:53 pm Wednesday, May 30, 2018

Ask a Trooper by Troy Christianson


Question: I see vehicles with straight pipes, motorcycles with straight pipes and hear many others that sound as if they have no muffler. If the law is there why is it not enforced?

Troy Christianson

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Answer: Minnesota State Statute 169.69 states: “Every motor vehicle shall at all times be equipped with a muffler in good working order which blends the exhaust noise into the overall vehicle noise and is in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle on a street or highway. The exhaust system shall not emit or produce a sharp popping or crackling sound. Every motor vehicle shall at all times be equipped with such parts and equipment so arranged and kept in such state of repair as to prevent carbon monoxide gas from entering the interior of the vehicle.  No person shall have for sale, sell or offer for sale or use on any motor vehicle any muffler that fails to comply with the specifications as required by the commissioner of public safety.”

The law does not specifically answer how loud a motorized vehicle can be, but it does say that a vehicle must have a good working muffler that prevents “excessive or unusual noise.” So any cutouts or bypasses, straight pipes or rusted out mufflers and exhaust with holes are illegal. After market mufflers, sometimes called “glass packs” or “cherry bombs,” can be an issue as they may produce “a sharp popping or crackling sound.”

Many counties and cities have local noise ordinances.  A noise ordinance defines which sounds are and are not acceptable at any given time. So depending on where you live, I would check with the local authorities on their ordinances.

This law is frequently enforced, and we do our best to educate the public on traffic safety and equipment violations through education and enforcement.

You can avoid a ticket — and a crash — if you simply buckle up, drive at safe speeds, pay attention and always drive sober.  Help us drive Minnesota toward zero deaths.

If you have any questions concerning traffic-related laws or issues in Minnesota, send your questions to Sgt. Troy Christianson, Minnesota State Patrol, at 2900 48th St. NW, Rochester, MN 55901-5848; or reach him at

Troy Christianson is a member of the Minnesota State Patrol.