Montana Department of Transportation

Malcolm “Mack” Long, Director


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Why Roundabouts?

Roundabouts are a safer alternative to traditional stop signs or signal-controlled intersections.

Fewer conflict points

Traditional intersections have 36 different points at which vehicles can crash into one another, compared to 20 points for a multi-lane roundabout.

Roundabout conflict points vs a regular intersection conflict points diagram

The roundabout’s circular design and one-directional traffic flow virtually eliminate the deadliest T-bone and head-on style crashes. Roundabouts also reduce rear-end crashes because traffic must slow down in order to enter.

Not just for cities

Roundabouts are proven to reduce fatalities and serious injuries at high-speed, rural intersections. Roundabouts at rural intersections were shown to result in:

90% reduction in fatal accidents, 75% in injury crashes, and 37% overall crashes

Safer for pedestrians, too

Slower speeds and one-directional traffic flow mean fewer crossing conflicts. Vehicles and pedestrians also have more time to react to one another.

Pedestrians at Roundabouts