"On average, they reduce serious injury at intersections 70 to 80 percent and fatalities by 90 percent," he said in an e-mail, noting that a quarter of the nation's 36,000 highway fatalities occur at traditional intersections.
More than 2,000 roundabouts have been built in the nation since 2000, experts say.
In Swedesboro, the $780,000 state-funded roundabout replaced an irregular crossroads where Center Square Road and Woodstown Road meet the north-south Kings Highway.
"If you don't live here, it was tricky," Swedesboro resident George Murphy said. "There were accidents there a lot."
County Engineer Vincent Voltaggio said the bad geometry of the intersection lent itself to a roundabout.
Putting in traffic lights would have required realigning one road, and the signal system would "need so many different phases it would not have functioned properly," he said.
Besides making the intersection safer for drivers, the roundabout is expected to slow traffic entering downtown Swedesboro, officials said.
According to the Federal Highway Administration website, roundabouts reduce traffic conflicts (for example, left turns) that are frequent causes of crashes at traditional intersections. Unlike with old-style traffic circles or rotaries, traffic entering roundabouts must yield to the circulating traffic.
Work on the circle started before Thanksgiving and posed challenges to nearby businesses, including a diner, florist, and car dealership.
The project could not have ended soon enough for Dena DiBenardo of Flowers by Dena, which opened in October. The store owner had to ride out Thanksgiving and Christmas with road closings and detours.
But DiBenardo said she thought the roundabout would help in the long run.
"A lot of people avoid this area. It was scary," she said of the old intersection.
As for New Jersey's traffic circles, their numbers are down to about 20 from more than 100 in the 1950s.
There was no concerted campaign to blot them from the landscape, said Tim Greeley, a state Department of Transportation spokesman.
Many simply outgrew their usefulness in the face of increasing traffic and needed to be replaced, he said.
New roundabouts, in the meantime, have opened in Glassboro near Rowan University and near Camden County College in Blackwood.
Said Russell: "The modern roundabout . . . is almost totally different than the big, old, confusing, high-speed, high-risk, dangerous traffic circles or rotaries. The fact that they are round is about the only similarity."
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