Crash helmet required.

Mich. Comp. Laws § 324.82123, under NATURAL RESOURCES AND ENVIRONMENTAL PROTECTION ACT.

Mich. Comp. Laws § 324.82123

Sec. 82123. A person operating or riding on a snowmobile shall wear a crash helmet on his or her head. Crash helmets shall be approved by the United States department of transportation. This section does not apply to a person riding on or operating a snowmobile on his or her own private property.