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Indiana’s Roundabout-Obsessed City: Traffic Speeds Up by Going in Circles

The city of Carmel, Indiana, recently opened its 100th roundabout.

There will now be a short pause while you say, “Who cares?”

Actually, this is a significant milestone and something that should be of interest to American drivers. More and more U.S. cities are realizing what Europeans (especially the British) figured out years ago: Roundabouts are a good way to keep traffic moving while reducing fatalities and injuries, as well as fuel consumption and pollution.

For those unfamiliar, roundabouts replace traditional intersections (and their attending stoplights or stop signs) with a round loop of pavement. Cars drive into the loop and cruise around to their exit. The beauty of a roundabout is that it keeps traffic moving. Entrances have a yield sign rather than a stop sign, and as long as there are no cars coming from the left, there’s no need to stop.

Carmel’s mayor, Jim Brainard, began lobbying to replace intersections with roundabouts when he was elected in 1996, and the city’s rampant roundabout construction started that same year. (Ironically, Carmel was home to one of the country’s first automatic traffic lights.) Two decades later, Mayor Brainard is still in office, and Carmel is still building roundabouts — one hundred, to be exact.

What are the advantages? Cost is one: Roundabouts don’t require traffic lights or the electricity to run them. Traffic flow is another: A well-placed roundabout can handle more traffic than a traditional intersection, and there are no delays when traffic is light. Anyone who’s ever been stuck at a red light while absolutely no one drove through the intersection can appreciate this perk.

Carmel also cites significant increases in safety. The city says that when they compare their roundabouts to traditional intersections, they see a 40 percent decrease in accidents, with an 80 percent decrease in injury-causing crashes and a 90 percent decrease in fatalities. One key advantage is that traffic must slow down for a roundabout, as opposed to intersections where drivers often speed up to beat a red light (and risk a crash when they don’t make it).

Because roundabouts decrease needless stopping and idling, there are environmental benefits, too. It takes more energy to accelerate a car from a stop than from low speed, so a smoothly moving roundabout decreases fuel consumption and pollution.

Roundabouts are not a perfect solution. They can be a real pain for pedestrians, who must walk a lengthy circuit around the circle. Crossing a roundabout poses a bigger challenge for visually impaired pedestrians than an intersection with a stoplight and auditory walk/don’t-walk signals does. Some studies have shown that drivers are far less likely to yield to pedestrians when exiting a roundabout than entering it and that multilane roundabouts pose a higher risk to pedestrians than single-lane roundabouts. However, a European study determined that converting an intersection to a roundabout can reduce pedestrian crashes by 75 percent.

And then there are people who simply don’t understand how roundabouts work. Some stop at the entrance regardless of whether there are cars coming or not, risking a rear-end collision. Meanwhile, others barge into the roundabout without regard to cars bearing down on them. A 2013 study by the Insurance Institute of Highway Safety looked at two roundabouts in Washington State, and while collisions causing injuries or fatalities fell, the rate of noninjury crashes actually increased. They speculated that unfamiliarity with roundabout right-of-way rules was to blame — proper use of roundabouts is not always well-covered in the driver-education programs of states that don’t use them.

Once drivers get the hang of them, however, the advantages can be significant, and Carmel, Indiana, is forging ahead with its roundabout plans. The city plans to build some 30 new roundabouts over the next 2 years, while making improvements to others based on their experiences (such as sharpening the entrance angles, which reduces entry speed and improves traffic flow). The Federal Highway Administration want to see more cities follow Carmel’s lead — the agency is encouraging the use of roundabouts as a safer and smoother form of traffic control. Perhaps Carmel will turn out to be only one of several cities that reaches the 100-roundabout milestone.

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