Mich. Comp. Laws § 41.284
In lieu of borrowing money and issuing bonds or other evidence of indebtedness, the board of county road commissioners may advance the necessary funds for the construction of the proposed improvement from county road funds under its control, and, upon written certification by the board of county road commissioners that the cost of said improvement has been or will be paid from the county road fund, the county treasurer shall credit all assessments collected from the township at large and the assessment district, including any share of delinquent tax sales apportioned thereto, directly to the county road fund. Whenever funds are so advanced from county road funds, the township board of any township within which such improvement is located may, by resolution duly adopted, pledge the full faith and credit of the township to the repayment of all funds so advanced. In such case, if the county road fund has not been fully reimbursed by special assessment collections upon the final due date of the last installment of such special assessment, the township shall, within 90 days thereafter, pay to the board of county road commissioners such sum as is necessary to complete such reimbursement, and any delinquent special assessments thereafter collected shall belong to and be turned over to the township.
MCL 41.284