Seasonal Weight Restrictions Already in Effect in Several Michigan Counties
Lansing, MI – With another February thaw on the way, many county road agencies in the lower peninsula may implement seasonal weight restrictions by this weekend, according to the County Road Association (CRA) of Michigan.
Seasonal weight restrictions protect Michigan’s local roads from legal load weights as frost leaves the ground when they are most susceptible to damage. As a protective measure, restrictions are likely to be imposed by state, city and county road agencies to avoid permanent damage to the road caused by heavy loads when the support beneath the road surface turns to mush in the spring, and frost starts to leave the ground. Truckers and those hauling heavy equipment are the most likely to be impacted by the seasonal weight restrictions – which are sometimes called “frost laws.”
“Michigan law allows for local county road agencies to enact seasonal weight restrictions as necessary based on weather conditions,” said Denise Donohue, CRA executive director. “This year with a pronounced El Nino effect, our first county saw frost leaving the soil and put seasonal weight restrictions on in late January. It’s just Michigan weather.”
While roads are made of concrete and asphalt and look indestructible, they can actually be quite fragile in late winter as frost comes out of the ground. As frost melts just beneath the paved surface, the roadbed turns wet and spongy because water is trapped between the pavement and the frost beneath the water. When trucks and heavy equipment travel on these roads they can cause significant cracking and damage to Michigan’s already fragile roads.
On average, seasonal weight restrictions remain in effect for four to six weeks, depending on how rapidly frost in the ground melts. Soil type – which varies widely across Michigan – has a significant influence on the timing and duration of seasonal weight restrictions.
“In recent years, more county road agencies are consulting with neighboring counties to see if they can collaborate on the start and removal dates for seasonal weight restrictions, which benefits commerce,” Donohue said.
The 83 members of the County Road Association represent the voice for a safe and efficient local road system in Michigan. Together, they manage more than 73 percent of all roads in the state – more than 90,000 miles of roads – and 5700 bridges. It is the fourth-largest county road system in the nation.