Mich. Comp. Laws § 247.659
All roads, streets and highways included in the major street system of any municipality shall be officially known as city or village major streets as the case may be, and all roads, streets and highways included in the local street system of any municipality shall be officially known as city or village local streets, as the case may be. For a period of 2 years after the effective date of this act, the major street system and the local street system in each city and village, and the mileage in each such system used for all purposes under the provisions of this act, shall be as determined by the state highway commissioner, and thereafter the major street system and the local street system in each city and village, and the mileage in each such system used for all purposes under the provisions of this act, shall be as established by certification to and approval by the state highway commissioner pursuant to the provisions of this act.
MCL 247.659