Even though residents have been shoveling snow for weeks, a key sign of winter in Door and Kewaunee counties has yet to arrive.

Wisconsin’s frozen road law went into effect Sunday for the state’s two northernmost zones, which include U.S. 10 near Stevens Point, along with numbered state and federal highways north of U.S. 10.

The frozen road law allows vehicles hauling abrasives or salt for winter highway maintenance, as well as certain forest products, to carry additional weight. The declaration is issued once the ground beneath highway pavement is frozen to a depth of at least 18 inches, allowing vehicles to haul up to 18,000 pounds more than normally permitted.

The law does not apply to county or local roads, and drivers must still adhere to posted bridge weight limits.

The frozen road determination for Door and Kewaunee counties, which are located in Zone 3, will be made when conditions warrant. There are five frozen road zones in Wisconsin.