Delaware Code
Subchapter I. Equipment Requirements
§ 4317. Protectors or flaps behind rear wheels of vehicles.

(a) No person shall operate, cause or permit to be operated any bus or commercial motor vehicle having a gross weight of 8,000 pounds or more, including semitrailers and trailers, upon the highways of this State unless it is equipped with suitable metal protectors or substantial flexible flaps behind the rearmost wheels of the vehicle or combination to prevent the projection of rocks, dirt, water or other substances to the rear and to minimize side spray.
(b) The flap, shield or other device shall extend down from the vehicle's body to not more than 8 inches above the road surface, but not more than 15 inches when the vehicle is in an unloaded condition. The protector or flap shall extend laterally at least the width of the tire being protected.
(c) If any bus or commercial motor vehicle, including semitrailers and trailers, is so designed or constructed that the objectives in subsection (a) of this section are accomplished by reason of fender or body construction or other means of enclosure, either permanent or temporary, then the requirements of this section have been satisfied.
(d) This section shall not apply to any farm tractor or to uncoupled truck tractors or other vehicles where the construction is such that complete freedom around the wheel area is necessary to secure the designed use of the vehicle.
(e) The Director of the Division of Motor Vehicles shall set and adopt such regulations as are necessary to implement this section.
(f) Whoever violates this section shall for the first offense be fined not less than $10 nor more than $28.75. For each subsequent like offense, the person shall be fined not less than $28.75 nor more than $100.

Structure Delaware Code