Associated Press, Published May 28 2013
Minnesota experts, local officials hail roundaboutsST. PAUL – The rise of the roundabout in Minnesota is helping explain a drop in serious crashes.
State transportation experts say the circular intersections prove safer, more environmentally sound and better for the flow of traffic.
Traffic engineers in Fargo, where there are already eight roundabouts, also say they appreciate the design of roundabouts.
“I love ’em,” said Jeremy Gorden, Fargo’s transportation engineer. “They’re so intuitive. Getting to and through the intersection is really simple.”
In Minnesota, there are 115 roundabouts statewide, with another 39 planned or under construction. They’re used in place of right-angle traffic crossings.
In addition to the eight in Fargo, another two are being considered, Gorden said.
In Moorhead, there is only one Minnesota Department of Transportation roundabout south of town, according to project engineer Jesse Miller. Two new MnDOT roundabouts are being considered right now – one in Detroit Lakes and one in Alexandria – and there are a few other non-MnDOT roundabouts sprinkled throughout the region, Miller said.
Ken Johnson of the Minnesota Department of Transportation points to the state’s first roundabout near New Prague as proof of their safety value.
Before it went in, the intersection was the site of two deaths and 50 injury-causing accidents in five years. Since the roundabout was installed seven years ago, there have been no fatalities and only four injury crashes.
“The data show that they are the safest intersections we have,” Johnson said.
That meshes with U.S. Department of Transportation statistics that show roundabouts reduce fatalities by 90 percent. Around the country, multilane roundabouts have roughly the same number of accidents as signal-controlled intersections but 70 percent fewer injury-causing accidents.
The explanation rests with physics. At a traditional intersection, a motorist ignoring a signal can crash into the side of another vehicle, the most vulnerable part.
“Roundabouts eliminate that kind of crash,” said Washington County engineer Wayne Sandberg.
When drivers enter a roundabout, they slow their cars. So if there is a collision, it is most likely to be among cars headed in the same direction.
Roundabouts virtually eliminate all types of crashes at intersections, Gorden said.
“You really can’t get into a crash at a roundabout, unless you’re really looking to cause a crash,” he said.
The experts also highlight the effect of roundabouts on traffic flow. Cars travel through roundabouts an average of 10 seconds faster during rush hour, Johnson said. Because cars don’t come to a complete stop, there is less pollution from idling vehicles.
But the circular intersections don’t work everywhere. They require more land, and don’t tend to work on intersections where one roadway carries significantly more traffic than the one crossing it.
Also, Gorden said they work best with two-lane roads. Any wider, and the roundabouts aren’t feasible, he said. Plus, they’re “not simple” to plow in the wintertime, Gorden said, which can be troublesome in this part of the country.
The cost to build one isn’t much different than a standard intersection controlled by a stop light – about $1 million to $1.5 million, according to Minnesota officials.
Gorden said in his experience, roundabouts do tend to cost more than traffic lights – which can be as cheap as $200,000 for an intersection, he said.
And some drivers need time to adjust.
In Washington County, officials established Roundabout U, an outreach program teaching navigational skills. And drivers’ education programs are now encouraged to include segments on roundabout driving, Sandberg said.
Forum reporter Erik Burgess contributed to this report.