Circle the (station) wagons — more roundabouts are on the way.

Roundabouts are taking on a prominent role in Minnesota's transportation planning. More than 140 have been built since the state's first roundabout opened 20 years ago in Brooklyn Park, with the pace picking up rapidly in recent years. Another 40 are either under construction or in planning.

There are dozens of roundabouts in the Twin Cities, but you'll also find them in places like Fergus Falls, Grand Rapids, Rochester and Worthington. Blue Earth is getting three, and six are on the drawing board for Mankato.

Studies have shown that roundabouts have significant advantages over four-way intersections controlled by traffic signals. Roundabouts have fewer accidents overall, and far fewer that result in death or serious injury. They move traffic more efficiently and reduce vehicle emissions by 20 percent or more.

Several states, including New York and Virginia, have adopted a roundabout-first policy, making roundabouts the default intersection of choice. Minnesota hasn't gone that far, but the Minnesota Department of Transportation recently changed its engineering guidelines to give roundabouts equal weight with traffic signals in highway design decisions.

"By every technical, measurable criteria, the roundabouts are superior," said Mike Eastling, director of public works in Richfield, which has two major roundabouts and may soon build more. State officials echoed his comments.

"We like them, we're going to keep using them and we're going to keep putting them out there where we think they're appropriate," said Derek Leuer, a MnDOT traffic engineer.

Leuer said the department has tracked two dozen intersections that switched from signals to roundabouts and found about a 60 percent reduction in injury crashes and an 80 to 90 percent reduction in fatal crashes — all while moving more traffic through the intersections.

Widespread in Europe

Roundabouts have long been popular in Europe. France has about 30,000 of them; the United Kingdom has about 20,000. Germany, Spain and the Scandinavian countries also have tens of thousands of roundabouts, said Lee Rodegerdts, an engineering consultant with Kittelson & Associates of Portland, Ore. There are only about 3,000 roundabouts in the United States, but that number will continue to grow, he said.

Modern roundabouts are different from the traffic circles or "rotaries" found in some East Coast cities. Those rotaries, popular in the early days of the automobile, were built on a much larger scale than today's roundabouts. As traffic volume and speeds increased, the old rotaries became chaotic and unsafe, said Mark Johnson, a traffic engineer and roundabout consultant in Madison, Wis.

When America began to aggressively expand its highway network after World War II, engineers dropped the rotary in favor of signalized intersections. But other countries stuck with the roundabout concept. Over the years, they developed improvements that led to today's smaller, slower and safer roundabouts.

Roundabouts "are not just some Scandinavian social-science program," Johnson said. "They're based on a lot of traffic engineering science, developed primarily out of the U.K. and Australia.

"It's an engineering device to process traffic in an efficient manner," he said. "And they're unequivocally the safest form of intersection in the world."

Installing a roundabout typically costs about $1 million, while the hardware alone for a traffic signal costs about $250,000, Leuer said. But considering that signalized intersections often require rebuilding existing lanes and creating new turn lanes, the overall costs are comparable, he said.

With more than 250,000 intersections in Minnesota, there's little chance that roundabouts will ever predominate — nor should they. Engineers say they work best at the intersection of two roads with roughly equal traffic volume.

Not everyone is a fan

One of the state's busier roundabouts is at W. 66th St. and Portland Avenue S. in Richfield. Before it was converted to a roundabout in 2008, the intersection ranked as the third-worst in Hennepin County for the number and severity of crashes. In its first four years of operation as a roundabout, there wasn't a single severe crash reported at the intersection, although there were plenty of fender-benders as drivers adjusted to the unfamiliar feature.

That's the point, said Eastling. Roundabouts take the most severe collisions out of the equation: the head-on, the rear-ender, the high-speed T-bone caused by a driver racing to beat a red light. Cars move slowly but steadily through the roundabout, with an average speed of around 15 mph.

"You can get a sideswipe, a bump," Eastling said. "But nobody is thrown from the car."

Surveys have shown that before a roundabout is put in, about two-thirds of people are opposed to it. After two years of operation, the sentiment flips, with about three-quarters favoring it. Still, that leaves a hard-core minority of opponents. As the proprietor of the 66th and Portland intersection, it's a fact Eastling is well aware of.

"I guarantee you, there are people who will go to their grave hating that roundabout," he said.

One of them is Jerry Flategraff, a regular at the American Legion post bar a block away on Portland Av. Ironically, Flategraff is a former MnDOT employee who helped create the standards for roundabout signs — a job he called "a bear."

"Roundabouts should be in Europe, not the U.S.!" Flategraff exclaimed. "Left turn, right turn! That's it!"

Not so, said Bill Lindboe, seated further down the bar.

"The one out here is just fabulous. It does what it's supposed to do," he said. "You slow things down; it makes you respect the traffic. I think it's the greatest thing ever."

John Reinan • 612-673-7402