(1) The state and county auditors referred to by this part are required to audit the books and records of county highway commissions whenever they make an audit of other offices in the several counties of this state, but this does not apply to counties which have an auditing department or may hereafter have such department.
(2) Such report setting forth the result of their audit of the county highway commissions shall be filed with the county mayor within a reasonable time after the same has been completed and is subject to public inspection as other public records.