In an effort to reduce traffic congestion and improve flow at the Foys Lake Road intersection of the Kalispell Bypass, the state transportation department will remove the existing roundabout and replace it with an overpass, while also expanding a stretch of the roadway to four lanes.
With traffic volumes especially high during morning and evening work commutes, Montana Department of Transportation (MDT) officials say the roundabout has reached its capacity and can no longer maintain the traffic flow.
An estimated 23,000 vehicles use the roundabout daily, with 15,000 heading north or south and 8,000 heading east or west.
The high traffic volume at all legs of the roundabout means there’s almost constantly a vehicle in the interchange, which leaves somebody always waiting to enter and results in the traffic backup, according to Bob Vosen with MDT. Vosen says the roundabout does not keep a steady flow like it does in areas with a less directionally balanced intersection.
“If that 23,000 cars a day was 20,000 on the bypass and 3,000 on Foys Lake, it would probably carry it fine,” Vosen said at a Feb. 18 meeting. “It’s just the fact that it’s so much closer to even … it has a tremendous amount of traffic flow at all legs.”
Officials say the overpass design will be similar to the U.S. Highway 2 overpass, which allows free-flowing traffic with a bridge and southbound and northbound on and off ramps.
A $12.75 million Better Utilizing Investments to Leverage Development (BUILD) grant, along with a contribution from MDT, will fund the project, which is expected to cost at least $15 million.
Traditionally a design-bid-build project, the MDT is moving forward with a design-build project instead to accelerate the schedule before the BUILD grant expires. This means that a contractor and an engineering firm will partner to deliver the project, officials said. Vosen says this process will save roughly three years on the project.
Construction is planned to start this fall and proceed through the winter with a tentative plan to finish by the end of summer 2022.
Separately, the MDT is working to redesign the southernmost one-and-a-half mile section of the Kalispell Bypass, including the Airport Road and Basecamp Drive intersections, with plans to create four lanes to address traffic congestion. This project has not yet been funded and would likely not begin until 2025.