Michigan Compiled Laws, Chapter 123. Local Government § 123.68

Sec. 8.(1) A person who violates a posted rule or regulation made pursuant to section 6 or 6a  1 is guilty of a misdemeanor, punishable by imprisonment for not more than 90 days or work in a park cleanup program as an alternative to the imprisonment, or by a fine of not more than $500.00, or both.

(2) A rule or regulation adopted under section 6 that regulates a recreational trailway is not effective unless it is posted and maintained near each gate or principal entrance to the trailway.

(3) The operation of a vehicle on a recreational trailway at a time, in a place, or in a manner prohibited by a rule or regulation adopted under section 6 is a municipal civil infraction, whether or not so designated by the rule or regulation. A civil fine ordered for a municipal civil infraction described in this subsection shall not exceed the maximum amount of a fine provided by the rule or regulation or $500.00, whichever is less. An act or omission described in this subsection is not a municipal civil infraction if that act or omission constitutes a violation or crime that is excluded from the definition of municipal civil infraction in section 113 of the revised judicature act of 1961, Act No. 236 of the Public Acts of 1961, being section 600.113 of the Michigan Compiled Laws.