Frost law
Frost laws are seasonal restrictions on traffic weight limits and speeds on roadways subject to thaw weakening. In climates that experience below-freezing temperatures, damage to roads from thaw-weakening have led to many US states, Canadian provinces and other jurisdictions to enact laws that restrict vehicle loads during spring months, when road structures are thawing from above in a manner that limits water from escaping the soil structure, thereby weakening the pavement underpinnings.