2021 Montana winter frost/spring thaw laws and seasonal weight restrictions.

Typically seasonal weight restrictions start in December. However, you will need to check with the Montana DOT first if considering travel during the winter months. You can phone them: (406)444-6372 or visit their website for live information: https://www.mdt.mt.gov/travinfo/restrictions.shtml

2021 policy update: load and speed limit.
Special winter permits.

Weight restrictions.

The load limit of any single axle is 8 tons. On any tandem axles is 16 tons or 400 lbs. per inch width of the tire. No single axle may exceed 16,000 lbs. No tandem axles may exceed 32,000 pounds.

Front axle: 600 pounds per inch width of tire will be allowed regardless of the seasonal load limit in effect.

Current closures.



See also:

Tire chain laws.
Tire chain laws by location.
Trucking regulations.
Federal bridge formula.
Exemptions from seasonal restrictions


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