The office of highway engineer is abolished in all counties of the first class not having a charter form of government. In all counties having a county highway administrator rather than a county highway engineer, the county highway administrator shall perform or cause to be performed all duties required by law of a county highway engineer, except as otherwise provided in sections 61.011 to 61.156. Any reference in the revised statutes of Missouri to a highway engineer of a county of the first class shall after September 28, 1973, and insofar as consistent with the provisions of sections 61.011 to 61.156 refer to the county highway administrator in counties of the first class not having a charter form of government.