The ideal intersection, in a roundabout way

Posted on 19. Apr, 2012 by in Academic Departments, Civil and Environmental Engineering, Issues, Magazine, Research, Transportation Infrastructure

They’ve become the subject of myriad YouTube “how-to” videos. Entire department of transportation websites explain how to navigate them. And, they elicit more than a little anxiety and confusion in the minds of drivers entering, circling and exiting them.

Yet, roundabouts are rapidly cropping up in locales ranging from city streets to rural intersections and Interstate off-ramps. In essence, they are the “next big thing” in roadway intersections. Quite simply, roundabouts provide drivers an efficient, safer alternative to traditional four-way intersections governed by stop signs or traffic signals, says Civil and Environmental Engineering Professor David Noyce.

An expert in transportation safety, Noyce directs the Wisconsin Traffic Operations & Safety (TOPS) Lab  at UW-Madison. “In typical traffic engineering, there’s a tradeoff between safety and operations. Generally, ‘safe’ equals ‘inefficient,’” he says. “Our research has shown roundabouts offer benefits in both of these.”

TOPS researchers have studied not only roundabout safety and operations, but also the inner workings of seven software packages transportation engineers use to design roundabouts. At the national and international levels, their research not only can improve roundabout design software, but also inform traffic engineers’ decisions related to how to design roundabouts and where to construct them.

In Wisconsin, drivers can encounter any of 150 roundabouts already installed on streets and roads, with another 150 planned by the end of 2015. For one comprehensive evaluation, TOPS researchers studied crashes in 14 Wisconsin multi-lane roundabouts throughout the state. “Even if something happens, your risk of a fatal crash goes way down,” says Andrea Bill, TOPS traffic safety engineering research program manager.

In Wisconsin, as well as at the national level, roundabouts have emerged as being very safe, says Noyce. “You may not like them personally, but roundabouts have significantly reduced the probability of a severe accident happening,” he says. “I think that’s a contribution to society.”

Read a longer version of this story here.Bucky Badger head

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