(1) If a vacancy occurs in the office of the chief administrative officer, a qualified successor shall be chosen in the manner specified by law.
(2) If the vacancy occurs as a result of death, resignation or removal of the chief administrative officer, then during the period of time from when the vacancy arises until the time that a qualified successor is chosen, the duties of the chief administrative officer shall be performed by the assistant superintendent of highways, chief foreman, administrative assistant or other highest ranking member of the office of the chief administrative officer, who shall be designated as an interim successor by the chief administrative officer of the county highway department. The chief administrative officer shall designate the interim successor, in writing, by either name or title or position held. The interim successor shall fulfill all duties of the office of chief administrative officer as prescribed by law.
(3) If the county in which the chief administrative officer serves is a county that has an elected highway commission, then the chief administrative officer shall file the written interim successor designation with the chair of the county highway commission and with the county clerk. If the county in which the chief administrative officer serves is a county that does not have an elected highway commission, then the chief administrative officer shall file the written interim successor designation with the chair of the county legislative body and with the county clerk.