1. Whenever the county highway engineer of any county, or in any county in which there shall be no highway engineer, such other officer as the county commission may designate, shall find that any county road or bridge of such county is in such a condition that use thereof by vehicles of the weights specified in section 304.180, will endanger the road or bridge, or the users thereof, the county highway engineer may with the approval of the division engineer of the state transportation department whose division includes the area in question establish maximum weight limits for vehicles using such road or bridge in such amounts as will preserve the road or bridge and provide a reasonable margin of safety to the users thereof. Notice of any such weight limit established shall be given by posting signs at convenient and public places along any such road, and in conspicuous places at each end of any such bridge.

2. It shall be unlawful for any person to operate a vehicle of a weight in excess of the maximum limit established pursuant to the provisions of this section on or over any road or bridge upon which such maximum weight limits have been established unless the person shall have the express permission of the officer empowered to establish such limit.

3. Any person who shall violate the provisions of this section shall be guilty of a class C misdemeanor, and shall be liable in a civil action for any damages to the road or bridge.