The Michigan Department of Transportation (MDOT) and local agencies continue to adjust annual spring weight restriction areas to protect roads.
Effective 6 a.m. Wednesday, April 12, weight restrictions will be lifted on all state trunkline highways from the southern Michigan border north to the Mackinac Bridge.
Frost restrictions are still in effect for the remainder of the state and will be imposed and enforced on all state trunkline highways north of the Mackinac Bridge. State routes typically carry M, I, or US designations.
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.
When roads that have been frozen all winter begin to thaw from the surface downward, melting snow and ice saturate the softened ground. During the spring thaw, the roadbed softened by trapped moisture beneath the pavement makes it more susceptible to damage. This contributes to pothole problems already occurring due to this winter's numerous freeze-thaw cycles.
MDOT determines when weight restrictions begin each spring by measuring frost depths along state highways, observing road conditions, and monitoring weather forecasts. Weight restrictions remain in effect until the frost line is deep enough to allow moisture to escape and the roadbeds regain stability.
For weight restriction information and updates, call 800-787-8960, or access this information on MDOT's website at www.Michigan.gov/Truckers, under "Restrictions and Conditions." All-season routes are designated in green and gold on the MDOT Truck Operators Map, which is available online. You also may sign up to receive e-mail alerts.
Trucking companies located in New Jersey and Canada can obtain information by calling 517-373-6256.