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What is a Roundabout?

Roundabouts are unsignalized circular intersections designed to maximize safety and minimize delay. Traffic circulates counter-clockwise around the central island. Entering vehicles must yield to all traffic already in the roundabout.

Roundabouts have many benefits, including:

  • Reduces injury collision by 75 per cent and fatal collision by 90 per cent.
  • Increases efficient traffic flow up to 50 per cent.
  • Overall reduction of collision by 30 to 40 per cent since their inception in North America.
  • Benefits the environment by reducing emissions, while decreasing fuel consumption by as much as 30 per cent.
Yield Sign

Yield: The Golden Rule of Roundabouts

When you enter the roundabout you must yield to circulating traffic. Yield means the other drivers in the circle have the right-of-way. An approaching motorist has to wait for a safe gap in the flow of traffic before entering.


Back to topRoundabouts in the Region

Brock St Roundabout

The Region of Durham is working to adopt the concept of a modern roundabout as a viable alternative to traffic control signals in specific rural locations.

The inclusion of modern roundabouts into North American design standards from their origins in Europe have led way to an overall reduction of intersection collisions by 30-40 per cent. More importantly, serious injury and fatal type collisions caused by right angle impacts can be reduced significantly. Unlike intersections controlled by traffic signals, motorists approaching a roundabout must yield the right-of-way to on-coming traffic and merge into the circle when it is safe to do so.

Prior to the installation of a modern roundabout, a "pre-screening" analysis is undertaken to ensure that a potential candidate site meets specific warrant criteria and that the installation will truly be in the interest of the motoring and tax paying public.


Back to topDriving a Roundabout

How to get around

  • Slow down when approaching the roundabout.
  • Keep to the right of the splitter island.
  • Be aware of your surroundings. Watch for pedestrians and cyclists.
  • Enter the roundabout only when there is an adequate gap in the circulating traffic flow.
  • Vehicles in a roundabout have the right of way and move in a counter clockwise direction.
  • Do not pass other vehicles or cyclists in the roundabout.
  • Always signal before exiting. Maintain low speeds.
  • Beware of pedestrians and cyclists crossing the road as you exit the roundabout.

Large Vehicles

  • Give other vehicles plenty of space.
  • The "truck apron" around the center island is for large trucks when turning.
Pedestrian Sign


  • Cross only at designated crosswalks.
  • Vehicles always have the right-of-way in the roundabout. Choose a safe time to cross.
  • Never cross to the central island of a roundabout
  • Step on the splitter island when crossing so you can safely cross one lane at a time.
Bike Sign


  • Experienced cyclists travel through the roundabout using the same general rules as any other vehicle.
  • Merge into traffic before entering the roundabout.
  • Once inside the roundabout, ride in the middle of the lane so cars don't pass you.
  • If you prefer to walk your bicycle on the sidewalk, dismount at the ramp. Continue on the sidewalks, following the same rules as pedestrians.
Emergency Vehicle

Emergency Vehicles

  • If you have not entered the roundabout, pull over to let the emergency vehicle pass.
  • If you are already inside the roundabout, do not stop. Continue to your exit, then pull over to allow the emergency vehicle to pass.



Back to topAlways Obey the Signs and Markings

As you get closer to the roundabout entrance, it is very important to observe the signs and arrows. Below are some of the signs you will see.

Roundabout Sign
Roundabout ahead, time to slow down.
Yield Sign Ahead
Yield sign ahead.
Stay Right Sign
Stay to the right of the splitter when approaching the roundabout.
Guide Sign
Guide signs near the entry show the correct exit to take.
Yield Sign
Yield to traffic on your left before entering the roundabout.
One Way Sign
Remember, all traffic within the roundabout travels one-way.


Back to topBenefits of Roundabouts

Roundabouts are becoming more common in North America due to their many benefits.


Roundabouts provide a superior safety performance than traditional STOP or signal controlled techniques. They reduce the number of conflict points and eliminate the most severe head-on and left-turn crashes from occurring. They operate at lower speeds and simplify the decision-making process as drivers only need to look in one direction for on-coming traffic.

Roundabouts reduce overall accident rates by approximately 35 per cent. Personal injury and fatal collisions have been reduced by 80 per cent.

Accident Reduction Graph


Roundabouts generally reduce vehicle delay by allowing motorists to YIELD rather than STOP at red signals. They are a good alternative at locations where there are heavy left-turn and fluctuating traffic patterns.

More Economical

Two lane roundabouts can compare favourably to the capital, operating and societal cost of a traffic control signal. However, the cost benefit is largely dependant on property acquisition and other capital cost which can vary substantially.


Roundabouts reduce fuel consumption and vehicle emissions because vehicles are not idling at red signals.

The centre island of a roundabout provides an opportunity to beautify the location with landscaping. Flowers or low lying vegetation can be placed in the centre island making the intersection aesthetically pleasing.


Back to topRoundabout Myths vs. Facts

Myth: Roundabouts cause more crashes than stop signs or signals.

Fact: Roundabouts have been proven to reduce overall accident rates by approximately 40 per cent. Also, injury accidents are reduced by 75 per cent and fatal accidents by 90 per cent.. The accidents that occur in roundabouts are less severe due to a reduction in right angle collisions.

Myth: The public will never accept roundabouts.

Fact: Residents and motorists typically challenge and oppose roundabouts. However, opposition generally changes to acceptance within the first year of operation.

Myth: Roundabouts are the same as calming circles.

Fact: Roundabouts and traffic calming circles may look similar, but their applications are very different. Traffic circles are typically installed as retro-fit traffic calming devices on local roads and have received mixed reviews due to their lack of implicit design consideration.

Myth: Roundabouts cost more than signalized intersections.

Fact: The cost of a roundabout and signalized intersection are estimated on a site-by-site basis. Roundabouts do require more land in comparison to signalized intersections. However, traffic signals require ongoing maintenance and energy costs. If the lands necessary for future roundabouts can be acquired in advance, modern roundabouts can be a very cost effective method for controlling traffic.

Myth: Roundabouts are not pedestrian and cyclist friendly.

Fact: Statistically, there are fewer pedestrian and bicycle collisions at roundabouts. Although the number of pedestrian crossings and/or predominance of seniors or disabled pedestrians must all be considered during the planning and design process.


Back to topMore Information

Printed roundabout materials:

Websites on Roundabouts

Canada Regional
U.S. National
US Regional
Other sites:


Back to topSend us your Questions and Comments

For questions pertaining to the operation of a modern roundabout, please contact:

Traffic Engineering & Operations
Works Department

P.O. Box 623
101 Consumers Dr.
Whitby, ON L1N 6A3

Phone: 905-666-8116

Fax: 905-666-8826