Ask A Trooper: Do vehicles need a working horn?
Question: I noticed that the horn on my vehicle does not work. Is there a law that that says a vehicle must have a working horn and when it can be used?
Answer: According to state law, your vehicle must have a horn that's "in good working order and capable of emitting sound audible under normal conditions from a distance of not less than 200 feet. The horn or other warning device must not emit an unreasonably loud or harsh sound or a whistle." I believe the definition of whistle is quite clear, and use common sense to determine if a horn is unreasonably loud or harsh. If it's too loud or harsh, it could violate a local noise ordinance.
Minnesota law says it's legal to honk a horn when it's "reasonably necessary to insure safe operation" on the road. For example, that'd include warning other vehicles, pedestrians or animals as needed to avoid a crash.
If it's not a safety situation, it's illegal to honk the horn on the road. Excessive or illegal use of the horn could result in a road rage scenario, so only use it when needed for safety.
A portion of state statutes were used with permission from the Office of the Revisor of Statutes. If you have any questions concerning traffic related laws or issues in Minnesota, send your questions to Trp. Jesse Grabow — Minnesota State Patrol at 1000 Highway 10 West, Detroit Lakes, MN 56501-2205. (You can follow him on Twitter @MSPPIO_NW or reach him at, firstname.lastname@example.org).