Spring weight restrictions more important than ever for protecting Michigan's roads

Contact: James Lake, MDOT Office of Communications,
 LakeJ1@michigan.gov
906-250-0993
Agency: Transportation

Fast facts:
- MDOT and local transportation agencies put weight restrictions in place each spring to protect roads.
- Spring weight restrictions will be announced by MDOT over the next few weeks.
- This past winter's extreme cold and lack of insulating snow is expected to make this spring's warmup tougher than usual on Michigan roads.

March 12, 2015 -- The Michigan Department of Transportation (MDOT) and local agencies are enacting spring weight restrictions on Michigan roads, an annual move to protect roads that's more important than ever.

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, similar to a sheet of glass supported by a waterbed. It's also the time of year when potholes begin forming due to the freeze-thaw cycle.

"Because frost has penetrated the ground so deeply this winter due to extreme cold and lack of insulating snow cover, we're expecting this year's spring 'breakup' to be worse than usual," said State Transportation Director Kirk T. Steudle. "A quick warmup like we're expecting will just make it worse. Aging pavements that are cracked already will be even more vulnerable."

MDOT determines when weight restrictions begin each spring by measuring frost depths along state highways, observing road conditions, and monitoring weather forecasts. In many parts of the state, frost depths currently exceed the limits of MDOT's frost tubes, which generally measure to 6 feet. Weight restrictions remain in effect until the frost line is deep enough to allow moisture to escape and the roadbeds regain stability.

"This time of year, our roads are under attack from above and below, with potholes forming in the surface and the gravel weakening beneath the pavement," Steudle said. "As the repair and maintenance needs continue to grow beyond the resources available to address them, we need to be more vigilant than ever in protecting our aging roads."

In 2013, MDOT spent $8.8 million filling roughly 415,000 potholes on state routes, and $10 million filling 650,000 potholes in 2014. MDOT is expecting this year's pothole season to be worse still, due to overall aging and deteriorating road conditions.

On state highways that are designated "all season," no overweight loads are permitted while seasonal weight restrictions are in place. On seasonal state highways, truck weights are reduced by 25 percent for rigid (concrete) pavements, and 35 percent for flexible (asphalt) pavements.

In order to protect roadway shoulders, which are not designed to carry regular traffic, permits for vehicles or loads exceeding 14 feet in width are not issued during seasonal restrictions.

County road commissions and city public works departments put in place their own seasonal weight restrictions, which usually, but not always, coincide with state highway weight restrictions. Signs are generally posted to indicate which routes have weight restrictions in effect.

Detailed weight restriction information is available at www.michigan.gov/truckers, or by calling 1-800-787-8960. See a video about pothole repair at www.michigan.gov/realitycheck.

MDOT says: Drive like you want to make it home tonight.

Related Documents
MDOT Reality Check #3 PDF icon
MDOT Weight Restrictions Graphic PDF icon