Frost Laws in North Dakota

The Longest Frost Law Season

North Dakota runs the longest frost law season in the northern plains: early March through mid-June. While Minnesota’s frost laws typically wrap up by mid-May and South Dakota’s end by April 30, North Dakota’s northern latitude and severe winters keep the ground frozen deeper and longer, extending the thaw vulnerability well into summer.

How North Dakota’s System Works

NDDOT sets weight restrictions as weather and roadbed conditions require. Unlike Minnesota’s zone-based south-to-north progression, North Dakota’s restrictions are implemented on a road-by-road basis as conditions warrant. Restrictions are lifted when roadbeds stabilize for legal-weight traffic.

Key Principles

• NDDOT monitors weather and road conditions continuously during thaw season
• Restrictions are posted when roadbed conditions deteriorate
• Restrictions are lifted when conditions stabilize — not on a fixed calendar
• Interstate highways are generally not restricted
• State highways and county roads bear the primary restrictions

Typical Timeline

The dates above are approximate and vary annually. A warm spring can compress the season; a cold, wet spring can extend it into late June. The 2024 season, for example, ran later than average due to a cold April.

Monitoring Resources

Check travel.dot.nd.gov daily during frost law season. Restrictions change as conditions evolve, and routes that were open last week may be restricted today.

Impact on Operations

Agricultural Hauling

North Dakota’s agricultural economy depends on spring movement of grain, livestock feed, and inputs. Frost law season directly conflicts with spring planting logistics. Grain elevators and farms sit on county roads that carry the heaviest restrictions. Planning around frost laws is a seasonal business reality for agricultural carriers.

Bakken Oil Region

The Bakken oil region in western North Dakota has its own frost law challenges. Oilfield access roads, many of which were built or upgraded during the boom, still face spring thaw restrictions. Operators should coordinate with oilfield service companies on access road status during thaw season.

Route Planning

The strategy is the same as in Minnesota: stay on interstates and major US highways during frost law season. I-94, I-29, US-2, and US-85 generally remain unrestricted. County roads and lower-class state highways carry the restrictions.

Frost Law Season Comparison

North Dakota’s season is approximately a month longer than its neighbors, reflecting its more severe winters and later springs.

The 105,500 lb Advantage

Outside of frost law season, North Dakota allows up to 105,500 lbs GVW on state highways (not interstates). This weight advantage partially compensates for the frost law disruption — carriers can move heavier loads during the months when roads can handle them. Route planning should account for both the seasonal restrictions and the post-thaw weight advantages.

Insurance Considerations

Frost law season does not directly change your North Dakota trucking insurance premiums, but it creates operational pressure that can lead to violations (overweight on restricted roads) and incidents (rerouting through unfamiliar roads). Adequate coverage protects against the cascade effects of frost law disruption. The $100,000/$300,000/$50,000 insurance requirement for OS/OW permits in North Dakota underscores the state’s recognition that heavier operations carry greater risk.