We were watching Alaska State Troopers last night and the narrator stated that all vehicles need mud-flaps. Never heard of that rule before:

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!


What do you mean, "there is no federal rule"?

Mudflaps are not addressed in the Federal Motor Carrier Safety Administration (FMCSA) safety regulations. Because the FMCSA regulations do not address them, they by default become a state issue. The bottom line is that it is left to the states to place regulations on the books to regulate the design and use of mudflaps (known in many states by their other name, splashguards), if they wish.

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!

While looking for this rule, it does not state anything about lifted trucks.

Being winter and all-this is something few of us think about.

Also I found this weird rule-13-ACC0225 Alaska vehicles are not required to have a windshield, but must wear eye protection. My mind is a whirl with possibilities HAHA other than the Antique cars.

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