Imagine cruising down the street at 45 mph with a line of green lights ahead. Your mind wanders. You don’t notice that one of the lights has changed to a yellow, then to red.
Before you know it, you’ve crashed into another car at a right angle — and maybe even killed the driver.
Instead, picture seeing a flurry of yield signs ahead and a roundabout with a steady stream of cars. Now, you’re paying attention.
“It makes the task of driving a little bit more difficult,” said Paul Atchley, a professor in traffic psychology at the University of South Florida.
That’s a good thing when it comes to making it home in one piece.
In Kansas City, speed demons zip past red lights, left turn lanes are a rarity and pedestrians play a deadly game of Frogger across wide, open roads. In four months in 2023, crashes killed five people along a 1.5-mile stretch of Truman Road between Benton Boulevard and Hardesty Avenue.
Citywide, nearly 200 people found out what happens when 3,000 pounds of metal meets human flesh in 2022 and 2023. A quarter of those crashes happened at intersections.
Those include the deadly intersection where high-speed Southwest Trafficway meets 39th Street, as well as the tangled six-way knot where 31st Street meets Van Brunt Boulevard, Stadium Drive, Hardesty Avenue, U.S. Highway 40 and Emanuel Cleaver II Boulevard.
Traffic signals mark the most dangerous intersections, where there are seven times as many deaths and serious injuries as there are at intersections with stop signs or roundabouts. Decades of research demonstrate that roundabouts are safer and less congested. But constructing roundabouts requires more land and complicated construction.
The case for roundabouts
A roundabout works by reducing the number of points in an intersection where two cars could collide. A traditional intersection has 20 to 30 conflict points. Roundabouts have eight.
That won’t always stop car crashes, but it makes them less likely.
And even if two cars collide, they’re moving in parallel — counterclockwise around the circle — rather than at a right angle. The car might take some damage, but those inside it will probably live to tell the tale.
“We cannot eliminate (crashes) because we have been trying for forever,” said Achilleas Kourtellis, an assistant program director at the University of South Florida’s Center for Urban Transportation Research. “But the idea is to look at it as a system and apply changes where they will (reduce) chances of having a crash.”
That’s why a 2022 traffic safety study recommended Kansas City adopt a “roundabout first” policy to bring down the rate of traffic fatalities — meaning that traffic signals could only be installed where a roundabout isn’t possible. Some states like New York have adopted similar policies statewide.
The Indianapolis suburb of Carmel went further. Since 1996, the city has built more than 120 roundabouts, replacing all but a dozen of its traffic signals.
Now, it boasts safer streets, reduced congestion and lower energy costs. The city says that air quality has also improved because fewer cars are idling at red lights.
Perfect in theory, complicated in practice
Kansas City isn’t going to replace every traffic light with a roundabout anytime soon. Nor should it, traffic experts say.
Part of the problem is that some of the city’s most dangerous streets are too busy for a roundabout.
At 31st Street and Southwest Trafficway, for instance, more than 30,000 vehicles pass through the intersection on the average day.
At such a busy intersection, Kourtellis said, “People are simply not going to have an opportunity to enter the roundabout.”
Instead, they’d end up waiting endlessly for an opening while traffic backs up behind them. And as crashes decrease at the converted roundabout, they might increase at another intersection when impatient drivers start taking an alternate route.
Kansas City’s traffic planners only consider roundabouts where there are fewer than 25,000 cars passing through every day, the city’s spokeswoman Sherae Honeycutt said.
That excludes just about any intersection on Southwest Trafficway, which sees more than 30,000 cars every day, plus cross traffic on 39th Street or Westport Road.
And denser areas, like Westport or Downtown, don’t have enough space. That’s why a proposal to install a roundabout at Southwest Trafficway and Westport Road fizzled out.
What’s more, roundabouts cost more to install than stop signs or traffic lights. Bigger roundabouts typically run $1 million to $3 million per intersection in Missouri.
Roundabouts are lower maintenance than traffic signals (and require no electricity), so they eventually reduce expenses in the long run. Ericka Ross, a district traffic engineer at the Missouri Department of Transportation, said they pay off in a 30-year lifespan.
But that up-front cost is nonetheless a barrier. A single roundabout could suck up more than a quarter of Kansas City’s total Vision Zero budget for 2024.
“These things take, unfortunately, years to design and build,” Kourtellis said.
This story was originally published by The Beacon, a fellow member of the KC Media Collective.
