The Free Press, Mankato, MN


October 13, 2012

Ask a Trooper: Loud muffler can be judgment

The Minnesota Court of Appeal [July 2006] * heard a case where the vehicle stop was for loud exhaust on a motorcycle (MSS 169.69 below). 

They upheld the law and affirmed the decision made in the District Court. 

The “MC Driver” held that the law was unconstitutionally vague and that therefore the officers did not have reasonable suspicion for the stop. Both Courts found that the officers, which were State Troopers, in fact made a good stop and sufficiently articulated the sound and condition of the exhaust, refuting the idea that the law or the officers’ articulation for the stop vague.

MSS 169.69 “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, … on a street or highway. The exhaust system shall not emit or produce a sharp popping or crackling sound”. For entire law visit:

Incidentally, after the initial contact/stop addressing the loud exhaust, the “MC driver” had strong indicator that he was impaired while driving the motorcycle; he was charged and convicted accordingly. The primary reason for the case if the reasonable suspicion is not establish for the stop then the defendant cannot be charged.

With this decision, it would be hard to dismiss because an actual measurement of the noise level was not provided and the law vague regarding noise levels. 

The Appellate Court’s Affirmation supports the District Court’s statement, “…a person of common knowledge, intelligence, and experience can easily determine when the noise from muffler or exhaust system does not blend into the overall vehicle noise or produces a sharp popping or crackling sound.”

I am unaware of any case since which has changed the view and decision of the courts.


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