Truck Mud Flap Laws

Mud flaps offer more than a utilitarian purpose, they can put a personal stamp on one’s truck.  Some are beautifully integrated into the truck’s design and others offer a political or personal statement.

Did you know that many states have laws regulating mud flaps?  They do.  Of course, everything else is regulated, so why not mud flaps?

Here are the mud flap laws:

The Mudflap Rule

One question that seems to get asked a lot is “Where are the mudflap rules?” This is especially true after someone receives a ticket for not having one!

The FMCSA recommends mud flaps be mounted at 300 mm and at angle greater than 22 degrees.

Most jurisdictions simply state that the vehicle must have mudflaps/splashguards on the rear of the vehicle that are adequate to keep spray and debris tossed up by the tires from hitting the windshields of following traffic.

Specific requirements

There are some states that provide specific requirements, and these are the ones that “set the standards” that interstate trucks need to follow. The most common requirements are that the mudflap/splashguard cover the full width of the tire and:

• Reach to within 8 inches of the ground (AZ, DE, MO, and TX are examples). Several states say the mudflap/splashguard must be within 10 inches of the ground.

• Extend down from the top of the tire at least the same distance as the width of the tires (MD is an example of a state that has this).

• Cover 2/5 of the vertical tire area (MS is 2/5, several states say 1/2 to 2/3). • Be able to stop water and debris that is leaving the tire at a tangent angle of 22

degrees or more (MI, OK, and PA all use the 22 degree standard).

So what can an interstate carrier do? To comply everywhere, most carriers go with a standard of around no more than 6 inches from the ground, but definitely no more than 8 inches from the ground (depending on where the fleet operates). This keeps you out of trouble just about everywhere you need to go!

*Information from JJ Keller