Frost Law Violations Can Affect CSA Scores

Frost Law Violations Can Affect CSA Scores

We see a lot of speed violations in states heavily pursuing frost laws where drivers should slow down 15mph under the posted speed limit.

Did you know there are 16 states and many Canadian provinces with frost laws? These include Idaho, Iowa, Maine, Michigan, Minnesota, Montana, Nevada, New Hampshire, New York, North Dakota, Pennsylvania, South Dakota, Vermont, Washington, Wisconsin, Wyoming, plus many Canadian provinces.

These laws are in place because when the frost melts beneath a paved road, the roadbed turns wet and spongy because water is trapped between the pavement and the remaining ice layer beneath.

What does this mean for drivers?

Well, a lot of permanent cracks can occur when heavy trucks and equipment travel over these weaker roads.

That is why some states implement seasonal weight restrictions, or “frost laws”, for certain roadways between February and May. So be ready for an alternate route or reduced speeds on roadways.

[Related: Top 5 Strictest Anti-Idling States Against Truckers]

These restrictions are also called “state trunkline roads” for state routes that carry the “M”, “I”, or “U.S.” designations (such as M-43, I-94 and U.S. 131). But there are some exceptions.

By law, road agencies can enact weight restrictions on any roads not designed as “all season” roads. All season roads are much thicker and designed to allow trucking year around.

Frost Laws can affect your CSA scores

Ignoring road signs may result in more than just a simple fine.

It may also result in damage to the roads, your vehicle, and/or cargo if the roadway is difficult to maneuver.

But what many professional drivers do not realize is that frost laws would cause at least TWO different violations:

  • “failure to obey traffic control device” (5 points CSA), and
  • “speeding [6-10], [11-14], or [15+] miles per hour over the speed limit” (4, 7, and 10 points CSA)

If the road was weight restricted only, then it would still be the failure to obey.

Note, general overweight citations are not a CSA violation in terms of actual Vehicle Maintenance BASIC violation points, except for “overweight on a tire”.


What are frost laws?

In many states, the axle weights are determined by actual conditions of temperature, moisture content in the soil, and observed road conditions. Also, it is important to note that several weight limits may be in effect in different parts of the state.

Trip planning is critical this time of year, so be sure to visit state websites to know if a specific highway is accessible to your vehicles.

For example:

  • In Pennsylvania, the commonwealth schedules seasonal weight restrictions from February 15th through April 15th. However, the state reserves the right to issue additional restrictions based on current weather conditions or upcoming storms in the forecast.
  • In New York, there are no annual standing seasonal weight restrictions in New York, but the state reserves the right to issue restrictions as conditions dictate. It is noteworthy that New York issues restrictions to ALL tractor trailers during periods of snow and snow removal on all major highways.
  • In North Dakotathere is a chart that categorizes seasonal restrictions each year by weight classes and axle groupings.

More importantly, in Michigan, the seasonal weight restrictions do two things:

  1. lower axle-loading limits
  2. reduce maximum travel speeds for certain vehicles

In Michigan, effective February 2nd, 2024, weight restrictions are imposed and enforced on all state trunkline highways, including the Upper Peninsula. State trunkline highways typically carry M, I, or US designations.

  • Michigan/Indiana and Michigan/Ohio state lines north to and including M-55 from the intersection with US-31 in Manistee,
  • then east on M-55 to the intersection with M-66 in Missaukee County,
  • then north on M-66 to the intersection with M-55 in Missaukee County,
  • then east on M-55 to the intersection with US-23 in Tawas City.

[Related: 12 Tips For Proper Trip Planning and Journey Management]

Michigan frost law 2024 road map

The maximum load allowed for concrete is 525 pounds per inch of the tire width and 450 pounds per each on any other Michigan road.

When it comes to speed restrictions, vehicles should move not faster than 35 miles per hour when traveling along reduced–load roads. 

Generally, the maximum axle load shall not exceed the number of pounds designated in the following provisions that prescribe the distance between axles:

  1. If the axle spacing is 9 feet or more between axles, the maximum axle load shall not exceed 18,000 pounds for vehicles equipped with high pressure pneumatic or balloon tires.
  2. If the axle spacing is less than 9 feet between 2 axles but more than 3-1/2 feet, the maximum axle load shall not exceed 13,000 pounds for high pressure pneumatic or balloon tires.
  3. If the axles are spaced less than 3-1/2 feet apart, the maximum axle load shall not exceed 9,000 pounds per axle.

A combination of vehicles may operate on designated highways with not more than 1 tandem axle assembly having a gross weight of 16,000 pounds per axle, if there is no other axle within 9 feet of the assembly.

On a combination of truck tractor and semitrailer having not more than 5 axles, 2 consecutive tandem axle assemblies may operate on designated highways at a gross permissible weight of 16,000 pounds per axle, if there is no other axle within 9 feet of any axle of either assembly.

Note: some limited classes are exempt from these restrictions after a permit is filed.

In the restricted areas, the following will apply:

  • On routes designated as “all-season” (designated in green and gold on the MDOT Truck Operators Map), there will be no reduction in legal axle weights.
  • On routes designated as “seasonal” (designated in solid or dashed red on the MDOT Truck Operators Map), there will be a posted weight reduction of 25 percent for rigid (concrete) pavements and 35 percent for flexible (asphalt) pavements.
  • All extended permits will be valid for oversize loads in the weight-restricted area on the restricted routes. Single-trip permits will not be issued for any overweight loads or loads exceeding 14 feet in width, 11 axles and 150 feet in overall length on the restricted routes.

For weight restriction information and updates, call 800-787-8960, or you can access this information on MDOT’s website at, under “Restrictions.” All-season routes are designated in green and gold on the MDOT Truck Operators Map, which is available online. You also may sign up to receive e-mail alerts.

Need Audit Help Now Or Want To Go Digital With DOT Compliance?

At CNS, our DOT Compliance Programs focus on Proactive Safety Management (PSM), a mindset that will ensure your fleet’s safety and compliance is always in order and ahead of the FMCSA.

We offer several different program levels depending on the size of your organization, however our PSM Motor Carrier Program is the more common when considering affordability and the comprehensiveness of DOT compliance assistance.

Our PSM Motor Carrier Program includes:

  • DOT audit support
  • ELD management
  • Driver Qualification File Management
  • New driver on-boarding
  • Driver safety meetings
  • CSA score management
  • Policies and handbooks
  • Vehicle maintenance
  • and more

Learn more about our DOT Compliance Programs

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