The Michigan Department of Transportation (MDOT) along with local agencies are making changes to their yearly spring weight restriction areas in order to preserve the condition of the roads.

Starting at 6 a.m. on Wednesday, April 12th, weight restrictions will be removed from all state trunkline highways from the southern border of Michigan all the way up to the Mackinac Bridge.

The frost restrictions will continue to be enforced throughout the rest of the state, and will be applied to all state trunkline highways located north of the Mackinac Bridge. State routes, which are usually identified by M, I, or US designations, will also be affected by these restrictions.

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.

As roads that have been frozen during the winter season begin to thaw, the melting snow and ice can saturate the softened ground beneath them. This softening of the roadbed due to trapped moisture can make it more vulnerable to damage during the spring thaw. This can further exacerbate issues with potholes, which have already been a problem this winter due to multiple cycles of freezing and thawing.

MDOT decides when to implement weight restrictions each year during the spring season by examining the frost depths along state highways, observing the overall condition of the roads, and monitoring weather forecasts. These weight restrictions remain in effect until the frost line is deep enough to allow moisture to escape, and the roadbeds can regain their stability.

To obtain the latest information and updates on weight restrictions, individuals can call 800-787-8960 or visit the MDOT website at www.Michigan.gov/Truckers, where they can find the “Restrictions and Conditions” section. MDOT’s Truck Operators Map also designates all-season routes in green and gold, which is available online. Additionally, one can sign up for email alerts on the same website to stay informed.