Mich. Comp. Laws § 254.59
Such county road commissioners shall have power and it shall be their duty to determine the number of annual installments, not exceeding 10, within which the money for the construction or reconstruction of any such bridge shall be raised. It shall apportion the whole cost of such work, in percentages, as between the special assessment area to be designated by them and whatever cities, villages and townships comprising said road districts and the county, or any or all of them, as in its discretion it shall determine. Such apportionment shall be made according to the benefits from such improvement accruing to the lands within such assessment area and the benefits to the public welfare and convenience of each of the cities, villages, townships and county, or any or all of them. The number of such installments, the road district aforesaid, the said special assessment area and said apportionment shall be designated and announced by said county road commissioners as soon as practicable after the approval of said specifications for said work. No township shall be entitled to any exemption from the payment of any assessment levied against it because of being entitled to the return of any county road taxes paid by it under section 26, chapter 4 of Act No. 283 of the Public Acts of 1909.
MCL 254.59