In an effort to curb damage to roadways in the northern United States, seasonal weight restrictions (also known as frost laws) are put into effect every year as the roads start to thaw out.
Typically, from March to May, authorities will limit the weight of trucks and/or speed of trucks that can travel on certain roads while the ground is soft.
Here’s every state that puts frost laws into effect and what you need to know when traveling in northern states in the spring.
States with Frost Laws
Idaho
Idaho will sign and mark affected state highways the day before the weight and/ or speed restrictions are in effect. On those sections of highways trucks and buses weighing 10,000 pounds or more will be restricted to 30 mph in critical areas. For specific information about which routes are posted, check out this link.
Illinois
Illinois has seasonal weight restrictions on non-state roads only. State roads do not have frost laws in effect.
Iowa
While Iowa does put frost laws into effect, specific information is difficult to find. Check this link for a map of counties with restrictions in place. Try this link for more resources.
Maine
Maine updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
Michigan
Michigan updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
Minnesota
While Minnesota does put frost laws into effect, specific information is difficult to find. Check this link for dates when restrictions go into place. Try this link for contact information for specific counties.
Montana
Montana updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
New Hampshire
New Hampshire updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
New York
New York updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
North Dakota
North Dakota updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
Ohio
Ohio has seasonal weight restrictions on non-state roads only. State roads do not have frost laws in effect.
Pennsylvania
Pennsylvania updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
South Dakota
South Dakota updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
Vermont
Vermont has seasonal weight restrictions on non-state roads only. State roads do not have frost laws in effect.
Washington
Washington provides an updated list of truck restricted roads online. However, roads with seasonal weight restrictions are not specifically listed there.
Wisconsin
Wisconsin updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.
Wyoming
Wyoming updates frost laws online so that you can always have the most up-to-date information. Find the latest info here.