Flathead County enacts seasonal weight restrictions on county roads

Weight restrictions for trucks on Flathead County roads are now in effect.  

Flathead County commissioners on Wednesday approved seasonal weight restrictions for select county roads in response to recent rapid temperature fluctuations and precipitation. 

Depending on whether the vehicle is single axle or tandem axle, trucks will be limited to 350 to 400 pounds per inch of tire. According to the approved resolution, total weight can range from 14,000 to 32,000 pounds, again depending on the number of axles. 

On most county roads, the load limit is 350 pounds per inch of tire width as marked with a 35 mph speed limit. 

As frost thaws beneath road surfaces, the underlying materials become saturated and unstable, making roads particularly vulnerable to damage from heavy vehicles. These seasonal restrictions help preserve infrastructure by considering factors such as axle count, vehicle weight, tire size, speed, and road conditions, according to the county.  

Dave Prunty, public works director, says he hasn’t seen such a rapid and drastic shift in temperature and road conditions.  

"In my 18 years with Road and Bridge, I’ve never seen such a sudden swing in conditions,” he said. “The ground beneath the roads is still frozen in some areas while completely thawed in others. This extreme shift has always been stressful on our roads, making seasonal weight restrictions necessary to prevent long-term damage."  

Drivers should watch for posted road signs and check Flathead County Roads and Bridges at flathead.mt.gov/department-directory/roads-and-bridges for updates.