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New boundaries announced for Wisconsin frost zones

December 5, 2013

With frozen road period expected to begin soon, WisDOT and trucking industry partners set new boundaries for four of Wisconsin’s five frost zones

With colder weather gripping much of the state, it’s expected that Wisconsin's frozen road law will soon be implemented – typically beginning in the northern portion of the state. Effective this winter season, the Wisconsin Department of Transportation (WisDOT) in cooperation with the trucking industry, have established new boundaries for four of the state’s five frost zones.

"The revised frost zone boundaries more accurately reflect typical weather and temperature patterns across the state," said David Vieth, director of WisDOT’s Bureau of Highway Maintenance. "Along with preserving highway infrastructure, these changes will support economic growth and freight movement by maximizing the frozen road period for each zone."

The state’s frozen road law allows heavier loads for trucks carrying peeled or unpeeled forest products cut crosswise (not including woodchips), or salt and sand for winter maintenance until approximately early March depending on weather conditions. The declaration is issued once ground under highway pavement is frozen to a depth of at least 18-inches. This allows the maximum gross weight for trucks hauling logs or salt and sand for maintaining winter roads to increase to 98,000 pounds on vehicles with a minimum of five axles (from the normal 80,000 pounds).

While none of Wisconsin’s frost zones have been declared frozen this winter season, an announcement impacting the northern portion of the state is expected soon – possibly next week. The boundaries for the northernmost zone – Zone 1 – remain the same, however borders for the state’s other four zones have changed. Further information on the new zones, weight restrictions and frozen road law can be found on the WisDOT web site.

For more information, contact:
Michael Sproul, WisDOT Bureau of Highway Maintenance
(608) 266-8680,



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