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2022 Winter Frost Laws, Thaw Laws, and Weight Restrictions

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2022 Frost Laws, Thaw Laws, and Seasonal Weight Restrictions

Learn the details of the winter frost laws, spring thaw laws, and seasonal weight restrictions in the USA states and Canadian provinces below. 

Frost/thaw damages to surface.
Frost/thaw damages to surface.

Many areas incorporate temporary particular weight limits and restrictions during the winter and spring months. These temporary restrictions are usually called “frost laws” or “thaw laws” and are implemented during March and April. However, in some Northern states and provinces in Canada, frost laws can still be in effect in July as it’s much colder. Since these restrictions are implemented on a “when needed” basis, the official government websites may not have published this temporary restriction in a convenient place. That’s because frost laws are subject to change at any moment based on the temperature of the core of the road. Therefore, you want to check with the appropriate officials to verify the latest changes in the laws.

2022 Frost Laws, Thaw Laws, Winter and Spring Seasonal Weight Restrictions in the United States

Here are 16 states affected by frost laws, thaw laws, and seasonal weight restrictions. These limits are affected by the current state of the road depending on the underlying road conditions, temperature, and soil moisture. Therefore, always contact the state highway department to be sure and keep in mind that the weight limits may differ in different parts of the state.



New York




North Dakota 







New Hampshire

South Dakota 


2022 Frost Laws, Thaw Laws, and Seasonal Winter Weight Restrictions in Canada

Frost laws, thaw laws, and winter weight restrictions in Canadian provinces change depending on the condition of the road. Therefore, it’s wise to look at the province’s website or contact the department of transportation to be sure.


New Brunswick 



British Columbia

New Foundland & Labrador 




Nova Scotia 

Prince Edward Island


Why Do We Have Frost Laws, Thaw Laws, and Winter Weight Restrictions?

The Northern US states and Canadian provinces rely on engineers and scientific data to determine when frost laws will be in effect to keep the trucking industry operating. Data is much more reliable with pretty recent advances in science and technology. That helps implement “Frost Laws” or “Seasonal Weight Restrictions” to ensure they aren’t implemented too early or late. While no State or Province desires to delay transporting goods through their territory, it’s crucial to protect public assets.
In areas that constantly get to below zero temperatures, the amount of damage has forced the Northern US States and Canadian Provinces to create and enact frost laws and weight restrictions. That restricts vehicle weights during the spring and winter months, specifically for trucking companies, since the roads and bridges are thawing out. There are all kinds of things that can go wrong with different types of roads and pavements. For example, the State of Michigan has implemented permanent frost laws that go into effect from March through May ( in some cases, even June). As a result, some routes require legal axle weight limits to be decreased by up to 35%. Some areas and local governments may also limit heavy-haul vehicle speeds to 35 miles per hour during frost/thaw law months, regardless of posted limits.

Oregon hwy. US 1. Photo courtesy of

One of many examples is in Southern Oregon on old US Highway 1, which follows the coastline from Mexico to Canada. The road is about 16 feet thick as years of pavement (even bricks) have been laid down yearly since the early 1900s. Keep in mind that today’s technology can provide us with flexible roads due to the engineering of the construction process and the materials used. However, excessive weight exerted by overloaded axles or a weakened supporting base can cause the pavement to bend or deform. The strength of the road, combined with its resistance to bending, determines the amount of weight the roadway can handle.

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


6 Responses

  1. We are (finally) adding frost law restrictions to the site. We’ll add the information published by each state or province with links for verification and additional frost law information; closure times/dates and weight limits and reductions. Thanks for your patience and it’s always better late than never!

  2. It would be very helpful to include the load restrictions help to protect the roads by dropping the legal axle weight of vehicles by 25% to 35% depending on road condition. The percentage does vary in some states with the frost laws.

  3. We’ve been doing some serious research and will be adding a whole new section detailing frost and thaw law restrictions in North America. Stay tuned!

    If you have any info you think would be helpful in our research please share it with us here…

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