Mud Flap Requirements and Specifications

Originally published in the September 2013 edition of Tech Trends (e-newsletter and as an article within NTEA News), this article is also available to you below as an employee of an NTEA member company.

A fairly common misconception is that mud flaps are a federally required item, like rear-end protection. Mud flap requirements on commercial trucks are actually state regulated, and each state may be a little different in terms of requirements regarding placement or height off of the ground.

Helpful Tip Regarding Mud Flap Guidelines

  • Most state regulations follow the Society of Automotive Engineers (SAE) recommended practice that the mud flap be at least the full width of the tire — and that the bottom of the mud flap is no more than 1/3 the distance from the center of the rear tire to where the mud flap is located. For example, if the mud flap is placed 42” behind the center of the rear tire, it cannot be more than 14” off of the ground.

More information available from the NTEA:

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