Spring weight restrictions will be lifted Monday morning on most state trunkline highways, but the move does not include much of the Upper Peninsula.

The Michigan Department of Transportation set the line for lifting the seasonal restrictions from the southern Michigan border north to and including U.S. 2/U.S. 141 at the Menominee River bridge west of Iron Mountain, then east on U.S. 2 to St. Ignace, then north on I-75 to M-134, then east to and including M-134 on Drummond Island.

The move takes effect at 6 a.m. Eastern time Monday, according to a MDOT news release.

Frost restrictions are still in effect for the rest of the Upper Peninsula on all state trunkline highways north of U.S. 2, I-75 and M-134 and on M-185 on Mackinac Island. State routes typically carry M, I, or U.S. designations, according to MDOT.

That means the restrictions will continue in most of Dickinson, all of Iron and in northern Menominee counties.

The region normally doesn’t see restrictions end until later in the year, sometimes into May, said Jim Harris, managing director of the Dickinson County Road Commission.

Local seasonal weight restrictions also remain and aren’t expected to change in the near future given the current wet conditions that weren’t helped by the snowfall earlier this week, Harris said.

While it appears the frost layer might be gone, “the saturation is mainly what we’re looking at (now),” he said, adding that the weightmaster is going out almost daily to check conditions.

County roads also are not built as durable as the standards required for state highways, so the county has to take more care to make sure local roads have the right conditions to withstand the weights.

Often the lifting of local restrictions will come earlier in the lower half of Dickinson County — south of M-69 — and later north to the Marquette County line, Harris said.

“It’s a different environment in the north and south of the county,” he explained.

The DCRC will update the public when any changes are made in the restrictions, Harris said, adding he is hopeful it might be a little earlier than normal given the mild winter.

In the restricted areas, MDOT advises:

— 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.

— 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.

— Routes designated as “seasonal” — designated in solid or dashed red on the MDOT Truck Operators Map — will have a posted weight reduction of 25% for rigid (concrete) pavements and 35% for flexible (asphalt) pavements, and maximum speed of 35 mph for some vehicles.

— Drivers must follow the speed limits for weight restricted roads, per state law. Speed restrictions for trucks and the rules for propane fuel delivery and public utility vehicles are available online at https://www.michigan.gov/mdot/.

Spring restrictions were put in place Feb. 2. MDOT explained that 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.

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.

For weight restriction information and updates, call 800-787-8960, or go to MDOT’s website at www.Michigan.gov/Truckers, under “Restrictions.” All-season routes are designated in green and gold on the MDOT Truck Operators Map, which is available online.

Trucking companies in New Jersey and Canada can obtain information by calling 517-373-6256.