The first roundabout I clearly remember was the one where I looked in my rear view window to see the flashing lights of a police car I had unwittingly cut off within its circle as I approached the outskirts of Wellington, New Zealand. I was seriously jet lagged, bemused by my first day of traveling on the left side of the road and not sure how to navigate such a big, busy, circular road.
I had nosed into the roundabout without much sense of what it was or how it was supposed to work, and come out the other side with a warning ticket. That was 2003. I now encounter roundabouts just about every day at some point, and I have learned to love them.
Roundabouts are becoming almost as common as potholes.
That’s a good thing.
Quite simply, roundabouts provide drivers an efficient, safer alternative to traditional four-way intersections governed by stop signs or traffic signals, says David Noyce, a University of Wisconsin-Madison professor of civil and environmental engineering.
An expert in transportation safety, Noyce directs the Wisconsin Traffic Operations and Safety (TOPS) Laboratory at UW-Madison. From Jan. 22-26, they discussed their roundabouts research in Washington, D.C., at the Transportation Research Board annual meeting, which draws more than 11,000 transportation professionals from around the world.
“People say they’re unsafe because it’s hard to judge the gap,” says Andrea Bill, TOPS traffic safety engineering research program manager. “But even if something happens, your risk of a fatal crash goes way down. We saw video of a driver traveling the wrong way, but everyone was driving through the roundabout so slowly, people could stop. There’s time to slow down and react.”
“The right-angle crash is one of the most severe crashes,” says Bill. “Roundabouts take away this possibility because drivers are always making a right turn. The crashes are less severe.”
While the initial construction cost of a roundabout varies site by site, its maintenance is cheaper than for intersections with signals.
I haven’t seen any studies about how much more soil they bury under asphalt, and that ought to be considered too.
3. Roundabouts are greener
Every bit as important, roundabouts reduce vehicle emissions and use less gas. According to the Insurance Institute of Highway Safety, In one study, installing a roundabout in place of an intersection with signals reduced carbon monoxide emissions by 29 percent and nitrous oxide emissions by 21 percent. In another study, replacing traffic signals and stop signs with roundabouts reduced carbon monoxide emissions by 32 percent, nitrous oxide emissions by 34 percent, carbon dioxide emissions by 37 percent, and hydrocarbon emissions by 42 percent.
Constructing roundabouts in place of traffic signals can reduce fuel consumption by about 30 percent. At 10 intersections studied in Virginia, this amounted to more than 200,000 gallons of fuel per year.
What do you think about roundabouts?
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