Mo. Rev. Stat. § 61.011: County highway administrator, office created, responsibility (certain first class counties).

1. The office of "County Highway Administrator" is hereby created in all counties of the first class not having a charter form of government. The county highway administrator shall be appointed by the county commission, and he shall serve at the pleasure of the county commission and until his successor is appointed and qualified.

2. The county highway administrator is the chief officer of the county in all matters pertaining to highways, roads, bridges, culverts and surveys, and he is responsible for all operations of the county highway department.