Roundabouts are (slowly!) eating the suburbs

Hillsboro, Va., recently added roundabouts at both ends of town to improve commuter flow from West Virginia to DC.
Hillsboro, Va., recently added roundabouts on both ends of the city to increase the flow of postal commuters from West Virginia to DC (Michael S. Williamson / The Washington Post)

Kiran

A quiet roundabout revolution is sweeping America’s suburbs. And it may have continued, unmeasured and unremarked, if not Lee Rodegerdts.

Apparently the good folks at the US Bureau of Transportation Statistics don’t track the nation’s traffic circles, loops or roundabouts. Indeed, no federal agency does. Instead, that heavy responsibility has, for a quarter of a century, fallen on the shoulders of Rodegerdts, an engineer and talented amateur photographer and pianist in Portland, Ore.

In the late 1990s, the Federal Highway Administration compiled the simple but amusing Rodegerdts to write a book in circles. The result is “Roundabouts: An Information Guide.” In the course of his research, Rodegerdts was surprised to find that no one had tracked the newfangled intersection mushrooming across the country.

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So he started counting. And he continues to count, through another edition of the guide, through dozens of round conferences and confabs, through Roundabout research projects and through Roundabout construction design is truly endless. His count soon migrated online, where he still spends his free time combing through submissions from a small army of amateur roundabouts, checking out new roundabouts and dating their construction using published reports and historical satellite photography.

When Rodegerdts started, he counted about 300 roundabouts nationwide. Just 25 years later, he counted about 9,000. And that doesn’t include the 160-plus rotaries or the 700-plus traffic-calming circles (which are very different from roundabouts).

Compared to the hundreds of thousands of normal intersections peppering the American landscape, ruled by stop signs and traffic lights, roundabouts are rare beasts. But unlike drivers they are often confused and bedevil, roundabouts come on quickly.

“People doubt that we can stay,” Rodegerdts told us. “But so far I think we have.”

Modern roundabouts rely on a geometric design that forces traffic to slow down, plus a simple innovation born in 1960s England: the rule that people in a roundabout have the right of way. In traditional rotaries and traffic circles, which still lurk in many East Coast cities, traffic flows faster and vehicles already in the roundabout often have to yield to newcomers.

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In the United States, the earliest roundabouts were often built in large cities. In general, our analysis shows, they are most likely to be built in highly educated cities. Today, the fastest growth is in the suburbs and rural areas.

“It’s very difficult to fit a roundabout into our dense urban environment,” Rodegerdts said. “And most of the roundabouts have gone in, either in new subdivisions or are intersections with existing — often suburban or rural — intersections.”

Why add a roundabout, you may ask. Because roundabouts offer impressive safety gains. Overall, a roundabout would reduce fatal crashes by 90 percent and reduce all car crashes by at least 75 percent, even while accommodating a greater volume of cars.

In a two-way stop in the village, the gains can be even more dramatic. Roundabouts can reduce all traffic injuries, both fatal and nonfatal, by nearly 90 percent. After all, it’s almost impossible to blow a circle at 60 miles an hour with a T-bone minivan – a very common occurrence at rural intersections.

“That’s the beauty of the roundabout,” Rodegerdts told us. “It’s the geometry. It’s the curves that do the work. And it’s not relying on traffic control devices as the only thing keeping you from crashing at high speeds.

So which country is roundest? Florida boasts the most roundabouts, but also has the third largest population in the nation. Nebraska has a lot of circles per person, but they’re spread over one of the rarest (and often most scenic) road networks in the country. Per mile road, Maryland actually emerges as the winner of the Roundabout.

City rankings, on the other hand, are almost useless. Almost any way you slice the data, the exclusive Indianapolis suburb of Carmel ranks as the nation’s circle capital. And, like Rodegerdts’ database, Carmel’s roundabout network is largely the work of one visionary — in this case, seven-term Republican mayor and prominent roundabout booster Jim Brainard.

A lawyer by training, Brainard’s experience with roundabouts when he took office in 1996 consisted of having seen several in Great Britain. But the modern intersection made an impression, and when his constituents demanded a safer, more walkable city, he thought he had a solution.

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Roundabouts were very rare in the United States back then. As one of the highest-income, most educated cities in the country, Carmel was fertile ground for traffic innovation. Still, it took some effort and a weekend research trip to Purdue University to convince city engineers, who were skeptical. (More than a hundred intersections later, Brainard said, that one time skeptic has become a sought-after leader in roundabout engineering and commanding general in the roundabout revolution.)

Most roundabout-inclined cities and counties have moved cautiously, but Brainard achieved the holy grail of free—revolutionary traffic signal roundabouts through greater power—and a bit of carefully structured public debt.

Brainard’s attitude is that if Paris can build a world-class, roundabout-infused urban area on a flat piece of unspectacular but fertile land, then so can Carmel (pronounced CAR-mull). He was cautious but bold, speaking of his goals in the terms of the era, referring to the empires and kings of Europe as he explained the need to build infrastructure for the next thousand years.

And king is almost the perfect job description for Brainard at this point. Carmel became a city in 1976, as White flight began to swell it and other suburbs. Brainard has now served longer than every other mayor in the city’s history combined (a fun fact we borrowed from Indianapolis Star columnist James Briggs). During that time, Brainard saw the city grow from 38,000 residents to more than 100,000.

As mayor, he has built 140-plus roundabouts, reducing traffic casualties so dramatically that local fire departments rarely use their Jaws of Life extraction tools. But roundabouts are just one pillar in Brainard’s larger plan to build a dense European-style city in central Indiana. To that end, he’s also added winding, leafy streets and a glittering concert hall that hosts everything from Carmel Symphony Orchestra performances to Michael Bolton holiday specials.

Why is the Midwest so fond of orchestras?

Roundabouts are a linchpin in Brainard’s vision of a walkable city. It’s not just because they are often more friendly to pedestrians, but because they can reduce pollution and allow designers to fit more traffic in a small space. In the key stretch of its main north-south drag, Carmel replaced five lanes of traffic with only two lanes and several roundabouts. Green spaces and sidewalks have sprouted where the route used to be, and the total flow of traffic on the road has actually increased.

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In all of Carmel, only nine regular traffic signals remain, Brainard said. And when he takes office next year, the city will be on a path of only one. Ironically, as a nearby plaque notes, it was the site of one of the first automatic traffic lights in the United States. And now, at least in Carmel, it will be the last.

“It’s in the middle of a small town that’s been there forever, and there are buildings on the four corners, so that’s what’s going to stay,” Brainard said, explaining that there’s no room for a roundabout at the site.

But “it’s quite safe,” the Mayor assured us. “You can’t drive fast through that area.”

Why? Because, he said, “We put a roundabout at each end!”

Hello! The Data Department would be nothing without your data-driven questions! We want to know what you are curious about. What city has the worst sprawl? Which country exports the most human hair? How many jobs is the Paycheck Protection Program correct? save? Just ask!

To get every question, answer and factoid in your inbox as soon as we publish, register here. If your question inspires the column, we will send the official button of the Department of Data and ID. This week, a button goes to our colleague Shira Ovide, who will be your Tech Partner if you Sign up for her new newsletter. Shira’s question about the revolving door got us thinking about the much maligned circular things that are actually more efficient. Another button goes to Rob DeRocker, the New York public relations professional who represents Carmel and who last year uttered the six most unpleasant words in the English language: “Let’s do a story about the circle.”

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