Mich. Comp. Laws § 254.51
Whenever in any county within this state there are any 2 or more organized townships, or any 1 or more townships and 1 or more villages, or 1 or more townships and 1 or more cities, or any combination of townships, villages and cities, or any combination of any of them, lying contiguous in such county, through the territory of which extends any public highway which crosses within said county and within or along the boundary line of any such township, village or city, any navigable water or stream, or which intersects with or leads to any highway so crossing such navigable water or stream, any 1 or more of such townships, villages or cities may, by its or their respective legislative bodies, petition the board of supervisors of said county for the construction or reconstruction of a bridge over such stream or water, whereon such highway may be continued as an avenue of public travel between points upon opposite sides of such water or stream. Such petition may be presented at any regular meeting of the said board of supervisors or at any special meeting thereof duly called for the presentation of such petition: Provided, That the provisions of this act shall apply only to counties having a population of 400,000 or more.
MCL 254.51