Michigan Compiled Laws, Chapter 257. Motor Vehicles § 257.728e

Sec. 728e. When under section 728  1 an officer issues a citation for a misdemeanor punishable by imprisonment for not more than 90 days, a magistrate may accept a plea of guilty or not guilty upon the citation, without the necessity of a sworn complaint but the officer shall sign the complaint before the magistrate makes a docket return on the complaint. If the offender pleads not guilty, further proceedings may not be had until a sworn complaint is filed with the magistrate. A warrant for arrest shall not issue for an offense under this act until a sworn complaint is filed with the magistrate.