photo: Mariusz Szczygiel/iStock

Road Rules Refresher: Traffic Circles and Roundabouts

By Craig Moy

Traffic circles and roundabouts are circular intersections where vehicles proceed in a counter-clockwise direction around a centre island. They’re intended to benefit both traffic flow—by eliminating timed stop signals—and road safety, by encouraging slower driving speeds and dramatically reducing the potential for T-bone and head-on collisions.

They are not, however, one in the same.

“Traffic circles are generally two lanes going in, two lanes coming around and two lanes exiting the circle,” says Rick Lang, of AMA Driver Education. “They’re reasonably large, and depending on the circle, traffic speeds can get up to 40 kilometres per hour.”

On the other hand, roundabouts are smaller in diameter and feature just a single driving lane. Drivers in roundabouts must slow down even more significantly—often to less than 30 kilometres per hour, Lang says—and pedestrian crossings are located away from the intersection.

For these reasons, roundabouts are nowadays much favoured over traffic circles when it comes to road design.

“Forty or fifty years ago, Edmonton a lot more traffic circles,” Lang says. “Now we’re down to just a handful.”

“But a number of roundabouts have been put in across Alberta—especially in newer areas of cities, and in some rural areas as well.”

The main thing to remember is that drivers entering either a roundabout or traffic circle must yield to drivers who are already inside. (If no one else is in the circle, you should still slow down, and be aware of pedestrians and cyclists.) Follow that rule—while properly signaling your intent to turn into and exit the roundabout—and you should be able to navigate through without difficulty.

Of course, there are a few finer points to consider, especially when it comes to multi-lane traffic circles.

Navigating a two-lane traffic circle
• When preparing to enter, scan for pedestrians and cyclists at crosswalks and yield to drivers already in the circle.

• Always enter, drive around and exit the traffic circle in the same lane. Do not change lanes while in the circle.

• Drivers intending to travel past the circle’s first exit should use the left (i.e. inside) lane to enter and exit. Use your left signal to show that you won’t be using the first exit.

• If you do happen to be in the right (outside) traffic lane, note that inside-lane drivers have the right of way. “With traffic circles, the number one mistake drivers make is that they fail to yield to the driver on the inside lane,” Lang says.

• When you want to exit, activate your right turn signal after you’ve passed the exit prior to your intended exit. Watch for pedestrians and, if you’re in the left lane, be aware of any vehicles in the right—in case they forget to yield. If it appears a right-lane driver isn’t going to yield, use your left-turn signal and continue around the circle to exit the next time around. Never “force” your way out of the circle from the inside lane.

Navigating a single-lane roundabout
• As with traffic circles, drivers entering roundabouts must yield to those already in the roundabout.

• If you plan to take the roundabout’s first available exit, use your right-turn signal as you enter and keep it on until you exit. Otherwise, for later exits, use the signaling technique noted above.

• Always scan for pedestrians and cyclists at crossings as you enter and exit the roundabout.

Following these guidelines will help ensure you proceed through circular intersections safely and without undue stress. And for a visual demonstration of our navigation notes, check out this video:

If you’re still uncertain about driving in traffic circles, hesitant about merging onto a highway or in need of a refresher for any other driving skills, consider signing up for a Brush-Up Lesson with AMA. It provides at least two hours of in-car instruction and can be customized to suit your needs.