Dr. Traffic

Use turn signal when leaving a roundabout

Roundabouts can improve safety by slowing traffic to 20 or 30 mph. T-bone crashes and head-on collisions tend to drop when all traffic is going in the same direction, according to N.C. DOT.
Roundabouts can improve safety by slowing traffic to 20 or 30 mph. T-bone crashes and head-on collisions tend to drop when all traffic is going in the same direction, according to N.C. DOT. N.C. Department of Transportation

There’s a reason why I sometimes wince at those weird intersections known as roundabouts, N.C. Department of Transportation’s James Dunlop explained.

“It’s making you think,” he said. “Instead of having a signal to tell you what to do, you have to think.”

Called out by a congestion management engineer. Boom!

But that’s not really it, I told myself later. There are just so many roundabouts now – at least 40 across our region that I could spot on Dunlop’s locator map. It shows 254 across the state, and there could be newer ones he hasn’t pinned, he said.

We’ve been dealing with these since 2000, when the first roundabout arrived at East Ninth and North Davidson streets in uptown, Dunlop estimates. Now there are two on Griffith Street in Davidson and two more at the Interstate 485/Moore’s Chapel Road interchange in western Mecklenburg County. The split-diamond interchange at I-485 and Prosperity Church Road has six roundabouts.

I grimace because people often don’t use a right turn signal when they’re ready to spin off the wheel and onto a connecting street. Sometimes they leave you hanging, and I’m not the only person bothered.

“Having lived in Europe for over 30 years, it drives me absolutely nuts when drivers don’t use the turn signal when leaving a roundabout,” a reader from Concord wrote. “They are changing direction and need to show it. People that want to enter the roundabout would definitely appreciate knowing.”

There’s another way to look at this, said Dunlop, a serious crusader for circular traffic flow. Even if you have to wait a little longer when drivers fail to signal, he said, the roundabout is usually more efficient than sitting at a red light.

“It’s the same as waiting at a stop sign,” he said.

Roundabouts also can improve safety by slowing traffic to 20 or 30 mph. T-bone crashes and head-on collisions tend to drop when all traffic is going in the same direction, N.C. DOT reports in “Your Guide to Understanding Roundabouts.” Crash rates have dropped by almost half where roundabouts have been installed at existing intersections, the guide says.

Cost savings can be one more benefit over traditional intersections. Three two-lane roads handle traffic at the I-485/Prosperity Church Road interchange, for example. Two lanes likely would have grown to three or four, including turn lanes, without the roundabouts, Dunlop said.

That means roundabouts probably are here to stay. So here’s what you need to know: Drivers in the roundabout have the right of way. At multi-lane roundabouts, move into a through lane or the right-turn lane well in advance, same as you would at a traditional intersection. Most importantly, use your signal when you exit a single-lane roundabout.

It’s something to think about.

Karen Sullivan: 704-358-5532, @Sullivan_kms

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