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Federal regulations
Montana has adopted Part 393 of the Federal Regulations.
Applicability
Part 393 applies to intrastate operation of vehicles with a gross vehicle weight rating, gross combination weight rating, gross vehicle weight, or gross combination weight of 26,001 or more pounds, or vehicles used to transport hazardous materials of a type or quantity that require the vehicle to be placarded.
First aid kit
No requirements.
Mudflaps
All trucks, truck-tractors, trailers or semitrailers moved on the highways of Montana shall be equipped with fenders, splash aprons or flaps designed, constructed and attached to the rear most wheels or set of wheels so as to arrest and deflect dirt, mud and water, rocks and other substances which may be picked up and thrown into the air by the rear wheels. If the vehicle is in excess of 8,000 lbs. gross vehicle weight (or rating), such fenders, splash aprons, or flaps shall extend downward to a point that is not more than 10 inches above the surface of the highway when the vehicle is empty.
If the vehicle is 8,000 lbs. or less gross vehicle weight (or rating), the fender, splash apron, or flap must extend down to a point that is not more than 20 inches above the road surface.
Studded tires
No tire may have a block, stud, flange, cleat, spike, or other protuberances of any material other than rubber projecting beyond the tread surface.
Exception — Pneumatic tires, embedded with wood, wire, plastic, or metal not protruding more than one-sixteenth of an inch beyond the tire tread may be used between October 1 and May 31 when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.
Tire chains
Tire chains of reasonable size may be used when required for safety because of snow, ice, or other conditions tending to cause a vehicle to skid.
Tire chains are required whenever the chain signs are posted.