Wis. Stat. § 345.52: No double prosecution.

(1) A judgment on the merits in a traffic ordinance action bars any proceeding under a state statute for the same violation. A judgment on the merits in an action under a state statute bars any proceeding under a traffic ordinance enacted in conformity with the state statute for the same violation.

(2) The pendency of an action under a traffic ordinance is grounds for staying an action under a state statute for the same violation. The pendency of an action under a state statute is grounds for staying an action under a traffic ordinance enacted in conformity with the state statute for the same violation.