U.S./Canada Mud Flap Requirements Guide

The U.S./Canada Mud Flap Requirements Guide provides a consolidated, searchable summary of current regulations for mud flaps, mudguards, and splash/spray suppression devices for commercial vehicles across both countries. It covers all 50 U.S. states, Washington, DC, and all 10 Canadian provinces and 3 territories.

There are no overarching federal or national regulations in either the United States or Canada governing mud flaps or splash/spray suppression devices. Instead, requirements are established at the state, provincial, and territorial levels — and they vary widely. Some jurisdictions enforce detailed specifications for trucks, trailers, and buses, while others have no specific requirements at all.

The U.S./Canada Mud Flap Requirements Guide is available free to NTEA members (login required).

Overview of mud flap regulations

• No national (federal) requirements exist for mud flaps or splash/spray suppression devices in the U.S. or Canada.
• Each U.S. state and the District of Columbia determines its own requirements.
• Each Canadian province and territory determines its own requirements.
• Some states, provinces, and territories do not have any mud flap/mudguard regulations at all.

State, provincial and territorial requirements

Use this Guide to quickly look up mud flap, mudguard and splash guard requirements, including links to official resources, for:

• Commercial trucks
• Trailers
• Buses

Key features include:

• Coverage of all 50 U.S. states, Washington, DC, and all 10 Canadian provinces and 3 territories
• An interactive list by state, province and territory
• Concise summaries of applicable regulations
• Direct links to statutes, regulations or ministry/department pages where available

Note: The Canadian summaries focus on requirements as they pertain to trucks. Buses and trailers may have different requirements.

Why compliance matters

• Safety: Helps reduce road spray and debris, improving visibility and safety for all road users.
• Legal compliance: Avoids citations, fines and other penalties for non-compliance with local requirements.
• Fleet maintenance: Limits damage to vehicles and equipment caused by stones, water and other debris.

Keeping up with regulation changes

Regulations can change frequently and may be interpreted differently by enforcement agencies. Always confirm details with the relevant authority before making compliance decisions:

• For U.S. requirements, consult the applicable state’s Department of Transportation (DOT) or equivalent agency.
• For Canadian requirements, consult the applicable province or territory’s Ministry of Transportation or equivalent agency.
• The Guide is periodically updated, but users should verify specific requirements as needed.

Additional resources

• Mud flap requirements for commercial vehicles (article)
• Technical resources

FAQ

Are mud flaps required by federal or national law in the U.S. or Canada?
No. There are no federal-level mud flap or splash/spray suppression requirements in the United States, and no national-level requirements in Canada. All requirements are established at the state, provincial or territorial level.

Do all U.S. states require mud flaps?
No. Not all 50 U.S. states have mud flap requirements for commercial vehicles, but most do: in fact, it’s 42 of the 50. Indiana, Kentucky, New Mexico, North Carolina, North Dakota, South Carolina, West Virginia and Wyoming do not have specific mud flap requirements (nor does Washington, DC).

Do all Canadian provinces and territories require mudguards or splash/spray suppression devices?
No. Many provinces and territories maintain their own unique requirements, while some do not have specific regulations in this area. The Guide provides a summary for all 10 provinces and 3 territories and identifies where requirements currently exist.