North Dakota frost law restrictions

2020 North Dakota winter frost/spring thaw laws and seasonal weight restrictions.

The North Dakota winter frost and spring thaw laws – seasonal weight restrictions. Seasonal weight restrictions are needed to protect the roads and highways during the winter months (usually between November 1 and April 1 each year but can extend towards the end of May) from being damaged by transporting heavy weights over them. While some of them are closed others remain open with weight limits significantly reduced in order to prevent damages. North Dakota implements protective measures to protect their infrastructure – and for a good reason.


Example of North Dakota frost and thaw law notification map for active months. Click to view their live version.

Make sure you’re educated on why the restrictions exist.

In most of North Dakota the colder winter temperatures cause the ground to freeze and become brittle. However, the earth underneath it is warmer and typically does not freeze so water exists in the roads aggregate when temperatures are frozen but not in the minus for long periods of time. What this does when large weights are transported over it is causes stress cracks and even buckling. These cracks lead to the deterioration of the road and eventually cause pot-holes as the ambient temperatures rise below thus expanding and pushing upward. The asphalt is then completely separated and a pot hole is created.

North Dakota spring thaw laws.

This is where any damages from driving over the roads during the winter frost months becomes evident. As the outside ambient temperature begins to rise so does the earths core. Since the asphalt is dense it takes it longer to thaw out. This is where buckling starts to take place as the warm earth expands and puts pressure on the asphalt to move upwards. This upward force causes the road to either buckle or pot holes start to develop from the millions of cracks that were created ultimately causing the public property to require maintenance which is a huge burden to the state and tax payers.

So North Dakota implements travel restrictions to prevent this.

With changing temperatures and built-up moisture in the pavement, roads are weakened as spring begins. Putting extra weight on the roads during this critical time can lead to even more issues. To prevent excessive damage to roads and highways, many states have enacted frost laws that go into effect during the early months of spring. These laws are designed to help protect the roads in areas with frigid winters.

Frost laws require that large vehicles carry a reduced load while driving on any posted or restricted roads. Also, heavy vehicles must lower their speed as the change in seasons takes place. This helps to cut down on the road damage that occurs as spring arrives each year is the notification system for North Dakota road closures.

North Dakota frost law Notification system and travel map.


See also:

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


North Dakota Shipping Regulations

2018 North Dakota DOT state shipping laws, regulations, rules and limitations for oversize and heavy haul trucking permits.


North Dakota heavy haul rules and limits for pilot cars.

The great state of North Dakota official seal

North Dakota State Trucking Permit Regulations.

North Dakota State Trucking information website:

Legal Loads.
Length: 75’ overall on non-designated highways
110’ overall on designated highways.
Weight: 80,000 GVW
Width: 8’ 6”
Height: 14’

North Dakota State

Routine oversize shipping, trucking and transport permits.
Length: 110’
Weight: Steer 12,100 lbs., Single 24,000 lbs., Tandem 45,000 lbs., Tridem 60,000 lbs., 4 axles 73,200 lbs., 5 axles 103,200 lbs., 6 axles 118,000 lbs., 7 axles 126,000 lbs.
Width: 18’
Height: 15’ 6”

How to apply for oversize transport and shipping permits.
North Dakota Highway Patrol
Motor Carrier Operations
600 E Boulevard Ave., Dept. 504
Bismark, ND  58505-0240

Phone: 701-328-2621
Fax: 701-328-1642

Basic Permit costs $20 and is valid for 5 days.  Applications can be printed here.

Pilot Car – Escort Car Requirements.

Width: 2 lanes  over 14’6” requires 1 front pilot car.  4 lanes over 16’ requires 1 rear pilot car. 2 lanes over 16’ requires 1 front pilot car and 1 rear pilot car.
Height: Over 18’ requires 1 front pilot car.
Length: Over 120’ requires 1 rear pilot car.

Travel Restrictions.

Travel is permitted from sunrise to sunset.  Travel permitted all weekend up to 16′ wide or 110′ in length. Continuous travel also permitted if heavy only.  When hauling a dozer the blade has to be attached when over weight.



The information contained in these pages is research information primarily for use by oversize and overweight trucking company drivers, dispatchers and pilot car companies. While every effort is put into maintaining the accuracy of this information you must absolutely verify this information with the North Dakota State DOT Permits office before commencing movement.




North Dakota state flag.