What is the mud flap requirement for trucks and trailers with four or more tires on the rear axle?

For trucks and trailers equipped with four or more tires on the rear axle, the regulation stipulates that mud flaps must extend to a height that is within 8 inches of the surface of the roadway. This requirement is designed to prevent debris, mud, and water from being thrown into the air by the tires, which can create hazards for other vehicles and impede visibility. Ensuring that mud flaps are positioned correctly is crucial for road safety, as it helps to minimize the risk of accidents caused by flying debris. The height limit is specific enough to balance the need for effective coverage while also allowing for safe operation of the vehicle.