Why is a roundabout the safest, most cost-effective solution?

When navigating roundabouts, drivers slow to 15 to 20 mph and travel in the same counterclockwise direction, significantly reducing the likelihood and severity of an accident. In addition, based on 50 years of traffic data assessed on this roadway and a thorough analysis of projected community growth, a roundabout will efficiently handle traffic volumes for the next 20 years without additional investment.

Roundabouts are highly effective in reducing crashes at intersections; the primary goal of this project. The Insurance Institute for Highway Safety found that on average, roundabouts reduce fatalities by 90%, serious injury crashes by 75%, and all kinds of crashes by 37%. Watch this video to learn more about why roundabouts reduce crashes.

Alternatives such as a traffic signal or four-way stop would simply serve as a device to assign right-of-way to traffic; they aren’t effective in reducing crashes. Furthermore, neither can prevent driver behaviors that often lead to crashes including the use of poor judgment or being distracted while driving. As an example, when seeing a yellow light, some drivers are more likely to race to “beat the light” which then increases the risk of a T-bone or head-on collision.

At the Dern/Springcreek intersection, the points of conflict will be reduced from 32, as it sits now, to just 8 once the roundabout is in place.

Conflicts images

Highway Configuration

Throughout the planning process, several community members have advocated for a three-way highway system. As with the notion of an overpass, this system has merits and was heard. The short answer is simply that funding is not available. This project, which can be funded with federal safety dollars, provides a solution for the immediate issue – saving lives at a deadly intersection.

Dern/Springcreek Versus Foys Lake

There are two important differences that differentiate the proposed roundabout at Dern/Springcreek from the Foys Lake roundabout. A considerable concern expressed by members of the public is, “If the Foys Lake roundabout isn’t working, why would MDT place a roundabout on another highly traveled highway near Kalispell? Clearly, based on the Foys Lake example, roundabouts don’t work here.” While this is a completely understandable assessment, it misses the larger picture of why the Foys Lake roundabout is over capacity and backing up during peak travel times.

  • Why is the Foys Lake roundabout failing during peak travel hours? Originally, MDT anticipated completing the bypass in its entirety (four full lanes for the length of the bypass and full interchanges at all but one intersection) in approximately 2030. With the fully developed infrastructure in place, the roadway would be equipped to carry the traffic volumes estimated for 2030. A combination of multiple beneficial factors, a primary one being funding, allowed MDT to advance full completion of the north half of the bypass approximately 13 years ahead of schedule, delivering it in 2017. Conversely, the roundabouts placed on the south end of the bypass were put in place as an affordable option in order to secure the first part of the bypass. They were instituted when MDT believed the entire bypass would be a two-lane system until approximately 2030 when funds would be available to complete all overpasses and transition the entire bypass to four lanes. This is called phased development and allows a mid-stage solution while monies are accrued and property is acquired for the final, permanent solution. MDT’s full plan was always to replace the Foys Lake roundabout and the Airport Road roundabout with overpasses and expand the south half of the bypass to four lanes. However, with the completion of the north end of the bypass, traffic volumes increased dramatically, reaching the 2030 projections almost immediately due to the route’s popularity. This 2030 traffic volume creates an especially large challenge at the Foys Lake roundabout, where the bypass transitions from four lanes to two lanes.

    In addition, Foys Lake roundabout has a relatively balanced amount of traffic on all four legs meaning north/south traffic is slowed as traffic from the east/west enters the roundabout. At present, this is creating significant congestion at the Foys Lake roundabout during morning and evening commute times. By comparison, the Airport Road roundabout has limited east/west traffic intersecting the bypass, and there is generally a free-flow of traffic moving along the north-south bypass route.
  • The Dern/Springcreek roundabout doesn’t face the same challenges that have created problems at the Foys Lake Roundabout.
    First, the Dern/Springcreek roundabout is on an established highway route (Highway 2 West). This means traffic trends can easily be tracked and future traffic volumes accurately predicted. From a traffic flow perspective, traffic volumes at the Foys Lake roundabout are more than double those clocked at the Dern/Springcreek intersection on Highway 2 West. Traffic models demonstrate that a roundabout at the Dern/Springcreek roundabout will efficiently manage traffic until approximately 2040. Also important is the fact that the vast majority of traffic will be traveling through the roundabout on Highway 2 West traveling either east or west. A very small percentage will enter from either Dern Road or West Springcreek Road, which will allow for essentially a free-flow of traffic on Highway 2 through the intersection. When vehicles do need to enter from either Dern Road or West Springcreek Drive, they will have a safe way to do so.