The Drive: Roundabouts are safer, MnDOT maintains

The Minnesota Department of Transportation recently released results of its most comprehensive study of roundabouts and found that the circular intersections are much safer than traditional intersections controlled by stop signs or stoplights.

MnDOT looked at the safety performance of 144 roundabouts by comparing before and after crash rates. The results showed that there has not been a multivehicle fatality in a roundabout in Minnesota. The study also found that there was an 86 percent reduction in the fatal crash rate at intersections where roundabouts were installed and an 83 percent reduction in the serious injury crash rate.

It's not that roundabouts are crash-free. In fact, crash rates in roundabouts are higher than most other types of intersections, the study found. But slower speeds and fewer T-bone or right-angled crashes — the kind more likely to lead to serious injuries or deaths — have made them safer.

"We will have property damage crashes," said Derek Leuer, traffic safety engineer with MnDOT. "We want to reduce the number of fatal and serious injury crashes. Roundabouts are effective in doing that."

Roundabouts have been part of the local traffic landscape since the first was built at Setzler and Neddersen Parkways in Brooklyn Park in 1995. Now there are about 200 across Minnesota, and more may be on the way, Leuer said. They are becoming more prevalent in greater Minnesota, partly because they are cost-effective and have lower life-cycle costs than a traffic signal with similar traffic capacity. Above all, "they are our safest intersections," he said.

Yet for many motorists, they are some of the most intimidating and misunderstood traffic control designs on the road.

"A lot of people did not grow up with them," Leuer said. "The first time they see a roundabout is when you are driving up to it and you don't know what it is, you don't know what the rules are, you don't know who yields to who. That can create a lot of issues."

A yellow warning sign will alert a driver that there is a roundabout ahead. Some roundabouts, such as the one at 66th and Portland, have two traffic lanes, which are more problematic than roundabouts with one. The key is to choose the correct lane before reaching the roundabout. If a driver wants to make a right turn at the intersection, pick the right or outside lane. Drivers who need to make a left turn should choose the left or inside lane. Drivers going straight can choose either lane.

When reaching the roundabout, drivers should slow down at the yield bar and allow traffic already in the roundabout to pass by. Drivers can enter the roundabout when there is a gap that allows the entering driver enough time to pull in and accelerate just like on a freeway, Leuer said. Once in the roundabout, keep a safe space between other vehicles, prepare to slow down to avoid a rear-end crash, and above all, stay in your lane until you've made it all the way through.

"People will switch lanes halfway through the roundabout and cross over the line," Leuer said. "We have a big problem with that."

Another tip: Semitrailer trucks using a multilane roundabout can use both lanes as the big rigs require a lot of space. Trucks can use the concrete apron to complete their maneuvers, he said.