Ohio Revised Code Title LV. Roads Highways Bridges § 5577.11

No person shall drive or operate, or cause to be driven or operated, any commercial car, trailer, or semitrailer, used for the transportation of goods or property, the gross weight of which, with load, exceeds three tons, upon the public highways, streets, bridges, and culverts within this state, unless such vehicle is equipped with suitable metal protectors or substantial flexible flaps on the rearmost wheels of such vehicle or combination of vehicles to prevent, as far as practicable, the wheels from throwing dirt, water, or other materials on the windshields of following vehicles. Such protectors or flaps shall have a ground clearance of not more than one third of the distance from the center of the rearmost axle to the center of the flaps under any conditions of loading of the vehicle, and they shall be at least as wide as the tires they are protecting. If the vehicle is so designed and constructed that such requirements are accomplished by means of fenders, body construction, or other means of enclosure, then no such protectors or flaps are required. Rear wheels not covered at the top by fenders, bodies, or other parts of the vehicle shall be covered at the top by protective means extending at least to the center line of the rearmost axle.