Mich. Comp. Laws § 224.27
Each county road commission shall contract with a certified public accountant to perform the audit. The proposed contract with the certified public accountant shall be confirmed by the county board of commissioners. Such audit shall be a public record and copies shall be sent to the county commission, the county treasurer and the state treasurer. If a county road commission fails to provide for an audit, the department of treasury shall conduct the audit or cause it to be conducted by a certified public accountant. The cost of any audit required by this act shall be paid by the county road commission audited.
Nothing in this act shall increase or decrease the powers, duties, and functions, including the authority to audit, of any state agency, department, board or commission relative to the boards of county road commissions as provided by any other law.
MCL 224.27