John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Maps and data visualizations show the U.S. trailing much of the world when it comes to traffic circles.
Intersections in America are boring: Grind to a halt, go left, right, or straight. Why can’t we be more like countries that forgo 90-degree angles for welcoming roundabouts, where drivers can ease into their exits or just circle repeatedly in automotive bliss?
Damien Saunder, a geospatial designer at Esri, recently found himself pondering this question. “I’m an Australian, and in Australia we have gone roundabout crazy!” he says. “Where I live now in California there are literally no roundabouts, so I set out to find if this was just a California thing or was it more widespread in the U.S.?”
What Saunder discovered, using data from Nokia’s 2014 Here maps, was indeed a deficit of domestic roundabouts compared with countries like France, where motorists are 25 times more likely to curve through one than in America. He also noticed U.S. roundabouts are not spread evenly throughout the land, but amass in certain places like Florida (1,283 roundabouts) and virtually disappear in others like the Roundabout Bermuda Triangle of Wyoming/South Dakota/North Dakota (not even 50 among the three).
Here are some more of Saunder’s findings, which he made into swell-looking visualizations. First, marvel at the huge number of angular intersections you must face before encountering a roundabout in the U.S.:
Saunder’s intuition about California being a roundabout desert didn’t pan out. It has the second-highest number of roundabouts in the country, behind Florida and ahead of Texas:
And here’s where American drivers are most likely to stumble upon a roundabout. If you judge by concentration in a state’s total intersections, it’s Maryland that comes out roundabout king:
Some argue the primitive roots of the roundabout actually grew in the U.S. “It’s widely accepted that William Phelps Eno was the bright spark who first devised the idea of a one-way rotary system in 1903, for Columbus Circle, New York City, USA,” asserts the U.K. Roundabout Appreciation Society, an organization rabidly opposed to “fascist, robotic traffic lights.” So why has the country fallen so far behind in deployment, given roundabouts’ elegant simplicity and proven safety benefits?
There are a lot of possible answers, says Lee Rodegerdts, an international roundabout expert (yes, they exist) at the Portland transportation-engineering and planning group Kittelson & Associates.
“My guess is that the possible benefit of roundabouts wasn’t widely known, and we had a long history of using traffic signals,” he says. “It took some bold people—both on the elected-official side and on the transportation-professional side—to get the first ones installed, and they deserve a lot of credit for sticking their necks out there. This boldness had to be repeated a lot around the U.S. during the [first] decade or two, given the skepticism of: ‘Well, that might work there, but it won’t work here.’”
Rodegerdts qualifies that there are disparities between Saunder’s analyses and those of transportation professionals, due to a difference in definitions. Saunder is using Nokia’s terminology of a roundabout being a “contiguous loop with consistent one-way traffic … that controls the traffic flow from converging roads” and a diameter (in most cases) wider than 82 feet. Rodegerdts prefers a stricter engineering definition given by the National Cooperative Highway Research Program. He estimates there were roughly 3,200 roundabouts in the U.S. in 2013; Saunder turned up 10,341 in 2014.
“There are relatively few true roundabouts in Texas, for example, and many of the circular intersections in Florida use stop signs at the entry or have yield signs within the circulatory roadway, which are inconsistent with the accepted practice at roundabouts,” says Rodegerdts.
Using the narrower definition would only widen the roundabout gap between the U.S. and other nations. America’s late start might be partly to blame. The U.K. had what are considered “modern” roundabouts by the 1960s, while America built its first one in 1990 in a Las Vegas subdivision, according to RoundaboutsUSA.
“So some of the difference is due to a longer history,” says Rodegerdts. “I believe the differences in the numbers may also be due to different levels of public investment in infrastructure, particularly with respect to addressing safety concerns where the roundabouts tend to perform quite well relative to other intersection forms.”
There are other, more controversial theories. “The roundabout is said to have flourished in Britain because it requires the British virtues of compromise and cooperation,” opines journalist Stephen Beard—who, no surprise, lives in Britain—writing in BBC America. “The U.S.’s more aggressive, confrontational culture may explain why the roundabout has not been more widely adopted by Americans.”
But Americans shouldn’t feel too bad about their cautious embrace of wonderful, whirling roundabouts, as other nations also lag behind. “For what it’s worth, other advanced countries are very early in their development of roundabouts, such as Japan,” Rodegerdts says. “They only have a few dozen roundabouts so far.”