Montana Department of Transportation

Public Involvement - Active Project

Broadus Interchange - Miles City

Broadus Interchange logo

Why Roundabouts?

Roundabouts dramatically reduce the frequency and severity of crashes compared to traditional stop controlled or signalized intersections. Over a 10-year period there were 40 crashes reported at the interchange, including 8 injuries. Crashes involving a rear-end or right-angle crash were among the most common reported.

Roundabouts naturally eliminate right-angle crashes through their circular shape and one-directional traffic flow. Rear-end collisions also decrease after the installation of roundabouts as traffic must naturally slow down to enter the roundabout. Roundabouts installed at similar intersections to the Broadus Interchange have been show to:

Car crash Graphic
Click on the image for a larger view

For intersections like the Broadus Interchange, roundabouts are an effective means of reducing peak-hour delays and improving traffic flow. By eliminating the need for vehicles to stop roundabouts promote continuous traffic flow during all hours. Drivers simply slow down, look to their left, and merge into the roundabout before traveling around the circle.

Locally Driven Solution

Roundabouts were the preferred intersection alternative identified by a citizens advisory committee composed of members with diverse local interests and backgrounds in the Miles City community. After considering a range of traffic control alternatives, including a traditional, signalized intersection committee members concluded that roundabouts would best address the current operational and safety concerns at the intersection, while accommodating future community goals such as improving access for bicyclist and pedestrians.