The highway administrator shall personally, or by deputy, regularly inspect the condition of all public highways, roads, bridges and culverts in the county, and in pursuance of orders of the county commission or upon the written complaint of three or more registered voters in the county directed to the highway administrator of a condition of disrepair of any road or highway or of a dangerous or unsafe condition of any highway, road, bridge or culvert in the county, or of the neglect of a contractor performing work of any character on any public highways, roads, bridges and culverts, the highway administrator shall investigate the complaint at once and report to the county commission and shall make such adjustment, repair or corrections as are necessary; and he shall make a written record or report of the final disposition of such complaint to the county commission.