Missouri Traffic Laws

Mud flaps Required, Certain Motor Vehicles. (RSMO 307.015)
1. Trucks, semitrailers, and trailers, except utility trailers, without rear fenders, attached to a commercial motor vehicle registered for over twenty-four thousand pounds shall be equipped with mud flaps for the rear wheels when operated on the public highways of this state.
2. If mud flaps are used, they shall be wide enough to cover the full tread width of the tire or tires being protected; shall be so installed that they extend from the underside of the vehicle body in a vertical plane behind the rear wheels to within twelve inches of the ground for dump trucks and within eight inches of the ground for all other vehicles required to be equipped with mud flaps under this section.

Mud flaps Required, Certain Motor Vehicles. (RSMO 307.015)

1. Trucks, semitrailers, and trailers, except utility trailers, without rear fenders, attached to a commercial motor vehicle registered for over twenty-four thousand pounds shall be equipped with mud flaps for the rear wheels when operated on the public highways of this state.

2. If mud flaps are used, they shall be wide enough to cover the full tread width of the tire or tires being protected; shall be so installed that they extend from the underside of the vehicle body in a vertical plane behind the rear wheels to within twelve inches of the ground for dump trucks and within eight inches of the ground for all other vehicles required to be equipped with mud flaps under this section.