Mud Flaps

PURPOSE: This rule describes the procedures and standards for the inspection of mud flaps. The inspection of mud flaps is a requirement of section 307.365, RSMo. (1) Trucks without rear fenders, which are intended to be registered for over twenty-four thousand pounds (24,000 lbs.) must be equipped with mud flaps for the rear wheels. Mud flaps must be wide enough to cover the full tread width of the tires. Mud flaps must be installed so that they extend from the underside of the vehicle body in a vertical plane behind the wheels to within eight inches (8") of the ground, except that mud flaps on dump trucks must be installed so that they extend from the underside of the vehicle body in a vertical plane behind the wheels to within twelve inches (12") of the ground. Mud flaps must be sufficiently rigid to provide adequate protection when the vehicle is in motion. (2) Fenders installed by the manufacturer on all pickup trucks and other small trucks will be recognized. Curved fender wells, such as those on gasoline delivery trucks, van-type trucks, and any other truck with a fender design that provides reasonable protection to the rear of the vehicle, will be exempt. (3) Reject vehicle if— (A) Not equipped with required mud flaps; (B) Flap is not wide enough to cover the full tread width of the tire(s); (C) Flap is not in a vertical plane extending to within twelve inches (12") of the ground for dump trucks; or (D) Flap is not in a vertical plane extending to within eight inches (8") of the ground for all other vehicles that require mud flaps. AUTHORITY: section 307.360, RSMo 2016.* Original rule filed Nov. 4, 1968, effective Nov. 14, 1968. Amended: Filed March 9, 1970, effective March 19, 1970. Amended: Filed Aug. 13, 1970, effective Aug. 23, 1970. Amended: Filed Nov. 9, 1971, effective Nov. 19, 1971. Amended: Filed May 21, 1974, effective May 31, 1974. Amended: Filed April 2, 1992, effective Sept. 6, 1992. Amended: Filed June 2, 1993, effective Nov. 8, 1993. Emergency rescission and rule filed Oct. 1, 1997, effective Nov. 2, 1997, expired April 30, 1998. Rescinded and readopted: Filed Oct. 1, 1997, effective March 30, 1998. Amended: Filed Oct. 30, 2020, effective June 30, 2021. *Original authority: 307.360, RSMo 1967, amended 1971, 1973, 1979, 1999.