Saskatchewan Frost Laws

2020 Saskatchewan winter frost/spring that laws and seasonal weight restrictions.

The winter/spring season frost law restrictions will again be in in effect for many roadways in the Province of Saskatchewan this year according to information provided by the the provincial Ministry of Highways and Infrastructure. Typically, seasonal (spring) frost law restrictions that take effect in March.

Spring load restrictions on affected highways: The maximum load on steering axles is 10 kg per millimeter (560 lbs. per inch) width of tire (manufacturer’s stamped dimensions), to a maximum of 3 000 kg (6,612 lbs.) on each wheel but to a maximum of 5,500 kg (12 120 lbs.) on the steering axle; except for straight trucks on primary highways which are allowed up to a maximum of 7,250 kg (15,983 lbs.) on the steering axle with the appropriate tire size.

Maximum loads on all other wheels will be limited to 6.25 kg/mm (350 lbs. per inch) width of tire to a maximum loading of 1,650 kg per wheel (3,636 lbs.)

Maximum gross axle weights and tire sizes.

Colder temperatures during the winter months help freeze and strengthen roads. As a result more weight can be transported on provincial highways without damaging the road. This is a benefit to the trucking community.

The winter weight period that allows additional weight typically runs from November 16 through March 14. However, if weather remains mild the program may be postponed because without sufficient freezing, extra weight can damage pavement and the road beneath.

Winter Weights will not apply in the southwest area of the province until December 1 and will be removed on the last day of February due to historically milder climatic conditions.

Municipal roads are the responsibility of each rural municipality, who can set out their own weight limits. Weights can be restricted at any time by Minister’s order.

Saskatchewan is a large province with considerable difference in climate in the north and the south. The new change takes into account the climatic differences in the north and the south of the province while also maintaining the original intent of providing primary weight access for economic activities. In the north of the province, the annual weight increase on the 9-month primary highways will be same as before, from July 1 to March 31 of the following year. In the south of the province, the annual weight increase on the 9-month primary highways will occur earlier, from June 15 to March 15 of the following year. This change will help to sustain road conditions in the south, where spring thaw occurs earlier.

Additional information can be obtained by contacting the inquiry line: 1-866-933-5290 in Saskatchewan or 306-933-5290 outside the province.

Source: Spring Road Restrictions:

Government of Saskatchewan, winter weight restrictions and spring frost law road bans and interactive road map:


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Prince Edward Island Frost Laws

2020 Prince Edward Island winter frost/spring thaw laws and seasonal weight restrictions.

Spring frost laws and weight restrictions for Island roads will begin at 12:01 a.m. on Friday, March 15, 2020.

Frost/thaw law for PEI.

For Prince Edward Island all weather roads, such as routes 1 and 2: Vehicles may carry up to their maximum allowable weight with no overweight exceptions permitted. Other roads: Vehicles may carry 75 percent of their maximum allowable weight during frost law (thaw law) season. Only the road’s posted weight limit is permitted and if the laws are not observed a fine may be levied.

It is important for truck drivers and trucking company dispatchers to make certain they are operating in accordance with the Prince Edward Island posted frost laws, seasonal load weight and speed restrictions that are posted. Changes to these restrictions is subject to change hourly during the winter and spring months. You are expected to be aware of these changes and operate accordingly. It is possible that heavy fines may be levied as well as your truck being ordered out of service and not permitted to travel. We suggest you bookmark this page for future reference.

Seasonal weight restrictions limit the maximum weight of vehicles allowed to travel on certain roads as a way to help prevent damage and protect investment in the roadways.

Late winter and early spring driving in this province has its own set of challenges. Previously frozen roads become more vulnerable to damage as they thaw out and soften. Heavy vehicles travelling over paved roads can make it worse by causing the pavement to crack and break up.

What is frost law and why are they necessary?

When pavement thaws during the daytime and freezes at night it is potentially damaging to the road. In order to prevent this “frost laws” are implemented in order to prevent costly damages to the road.

How are roads damaged by frost thawing or the road freezing?

Water from melted ice and snow seeps into cracks in the pavement and softens the gravel underneath. When the water beneath the surface freezes again, it expands and breaks the pavement, causing potholes. If ice continues to form under the pavement from a steady supply of water, it can push the entire surface of the road upward causing the washboard like unevenness (ripple) known as “frost heaving.” These damages are permanent and costly to repair.

Why are Prince Edward Island roads more vulnerable to seasonal damage?

Prince Edward Island consists of a high concentration of silty soil which collects and holds more water beneath the roadway surfaces, making the roads more susceptible to frost heaving and potholes despite any drainage measures that have been put into place.

What are the classifications of roads under weight restrictions?

  • All-weather roads, such as routes 1 and 2: Vehicles may carry up to their maximum allowable weight – with no overweight exceptions permitted.
  • Other roads: Vehicles may carry 75 percent of their maximum allowable weight.
  • Posted weight limits: Only the road’s posted weight limit is allowed.

Contact information:

Department of Transportation, Infrastructure and Energy
3rd Floor, Jones Building
11 Kent Street,
P.O. Box 2000,
Charlottetown, PE C1A 7N8

Phone: 902-368-5100
Fax: 902-368-5395

If you have questions about the frost/thaw laws as well as any other road related inquiries send a e-mail to:

Prince Edward Island seasonal weight restrictions:

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