Circular Logic: Why Roundabouts?

According to the Alaska Department of Transportation & Public Facilities (DOT&PF), in 2000 Alaska didn't have any roundabouts, but as of early last year the state had more than thirty-six, and that number continues to grow. Roundabouts are commonly included in new road construction, and many intersections across the state have been renovated to integrate roundabout designs. DOT&PF states: "The trend in Alaska mirrors the trend across the United States for a simple reason: [roundabouts] are much safer than a traditional signalized or four-way-stop intersection."

DOT&PF explains three primary reasons that roundabouts are safer: there are fewer collision points, fewer serious injury crashes, and increased safety for pedestrians.

There are thirty-two possible "collision points" in a traditional four-way intersection, as vehicles cross traffic while turning left, turn right on a red light, speed up to make the intersection before a light change, or engage in other typical intersection behaviors; however, in a roundabout there are only eight points of collision, four where vehicles enter the roundabout and four where vehicles exit.

When crashes do happen, they are less likely to result in serious injury or death. This is in part because a roundabout configuration almost eliminates the possibility of head-on and T-bone crashes. Vehicles in the roundabout are also traveling at a slower speed, which reduces the severity of the consequences of a crash.

And because vehicles move slower within and when entering and exiting the roundabout, both...