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Spring Brings Weight Restrictions on Michigan Roads

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Dirk H. Beckwith
Foster Swift Agricultural Law Update
March 14, 2014

It may not seem possible, but spring will come to Michigan after this long, cold and snowy winter. When it does, it brings its own set of problems, particularly to Michigan roads. As the ground begins to thaw, the surface of our roads becomes unstable, buckling and heaving.

To protect the roads, state law designates the months of March, April and May as reduced load months for trucks. The law is called the ‘frost law,’ referring to the amount of frost remaining in the ground. It is the warming and cooling of the ground that weakens the roads causing the roads to buckle, creating potholes and broken pavement. Heavy trucks and speed increase the damage brought by the change of season.

During those months, trucks traveling on “posted or restricted” roads must lighten their load and reduce their speed. The maximum axle load allowable on concrete pavements is reduced by 25 percent and by 35 percent on all other roads. The maximum wheel load shall not exceed 525 pounds per inch of tire width on concrete and 450 pounds per inch on other roads. The speed on reduced loading roads drops to 35 miles per hour regardless of the posted limit.

Your truck may not be affected by the frost laws. The following vehicles are exempt:

  • Vehicles transporting agricultural commodities, which are plants and animals produced by the farmer, but not including trees or lumber
  • Milk Haulers
  • Farm Equipment
  • Public Utility Vehicles

To receive the exemption, you must request a permit from your local county road department or road commission 48 hours before you travel on the restricted roads if your truck exceeds the weight restrictions. The local authority is required to issue a permit stating the date and time of travel, the route and the maximum speed limit. There is a fee for the permit.

The permit process is a step in the enforcement of seasonal weight restrictions. The laws also allow for fines and costs for violations of the seasonal weight restrictions. (MCL 257.724, 257.716)

The ‘frost law’ does not apply to all roads. The State posts the restrictions for the roads and highways under its jurisdiction while the local authorities announce the streets and roads under their control affected by the frost law. To discover which roads in your county are affected, you can check with your county road agency or the County Road Association of Michigan: micountyroads.org

For more information please contact Dirk Beckwith at dbeckwith@fosterswift.com or 248.539.9918.