Frost Law in Effect March 1, 2025

Published Feb. 27, 2025

Frost Law seasonal weight restrictions in effect in Dearborn beginning March 1, 2025

As of March 1, 2025, the City of Dearborn has put the Frost Law ordinance into effect. This means seasonal weight restrictions for axle and wheel loads are now in place.

Frost law refers to the amount of frost remaining in the ground. The warming and cooling of the ground during the changing weather and climate causes pavement to move and buckle, creating potholes and broken pavement.

During this time, the maximum axle load allowable on concrete pavements or pavements with a concrete base is reduced by 25 percent from the maximum axle load under normal loading. The maximum axle loads allowable on all other types of roads during this time are reduced by 35 percent from the maximum axle loads as specified.

The maximum wheel load shall not exceed 525 pounds per inch of tire width on concrete and concrete base or 450 pounds per inch of tire width on all other roads during the period the seasonal road restrictions are in effect.

On routes designated as "All Season Routes" (green or gold on the MDOT Truck Operators Map), there will be no reduction in legal axle weight, subject to Michigan Dept. of Transportation designation.

On routes designated as "Seasonal" (solid or dashed red on the MDOT Truck Operators Map), there will be a weight reduction of 25 percent for rigid pavements and 35 percent for flexible pavements.

Dearborn roads under local jurisdiction and subject to this chapter include, but are not limited to:

  • Schaefer Road
  • Southern Avenue
  • Outer Drive
  • Chase Road
  • Lonyo Avenue
  • Vernor Highway (weights must be restricted at 35 percent)

Seasonal weight restrictions help to preserve and protect against the wear and tear on city roads caused by the winter thaw and heavy vehicles. The Dearborn Police Department and other law enforcement agencies may enforce the seasonal weight restrictions and speed reductions while in effect. This is 35 MPH for trucks on applicable roadways.

The state highway commission, county road commission, or the city engineer have the authority to lift any road restrictions at any time, depending on the conditions of the highways or if there are any public health or safety concerns.

Detailed Weight Restriction information may be obtained at Michigan.gov/Truckers.

MDOT also has a Truck Operator's Map for route designations.

For more information, contact the Dearborn Police Motor Carrier Unit at 313-943-5468 or visit Dearborn.gov.

###

MDOT Michigan Truck Operators Map