FAQs About Roundabouts

Are roundabouts the same as traffic circles?

No. Roundabouts are smaller and require vehicles to go slower than traffic circles. The design of a roundabout controls the speed of vehicles at entrance and exit points, while the design of a traffic circle allows for higher speeds as vehicles enter and exit the intersection. The reduced speed of a roundabout results in fewer, less serious collisions. Roundabouts also provide easy pedestrian crossing points with clear navigation for vehicles and other road users. As well, traffic circles allow lane changes, while roundabouts do not permit lane changes.

How do you navigate a roundabout?

  1. Choose the appropriate lane before entering the roundabout (remember - lane changes are not permitted!). Advance signage and pavement markings will help you select what lane you need to be in to access each exit.
  2. Slow down as you approach the roundabout and yield to pedestrians.
  3. Look to the left and yield to all traffic inside the circular lane.
  4. Wait for an appropriate gap in traffic and enter when it is safe.
  5. Maintain a speed of between 30-40 km/h through the roundabout.
  6. Use your right turn signal as you approach the desired exit to indicate you are leaving the roundabout.
  7. Exit to your destination.

How do pedestrians use roundabouts?

Pedestrians use roundabouts with clearly marked crossings that are separated by a splitter island, which is a paved area between the lanes. There are no traffic signals to identify a "walk" phase, so drivers are expected to yield to pedestrians who wish to cross the street.

Roundabouts are designed to accommodate pedestrians and are generally safer than other forms of traffic control because:

  • Vehicle speeds are generally slower.
  • There are fewer vehicle/pedestrian conflict points.
  • Splitter islands provide a space for pedestrians to pause and allow them to cross one direction of traffic at a time. They also make the crossing distances shorter.
  • Pedestrians cross directly in front of drivers, making it easier for drivers to see and yield to pedestrian traffic.
  • Pedestrian crossings are setback one or two vehicle lengths from the yield line to provide better sight lines, shorter crossing distance and storage of vehicles yielding to pedestrians at the exit.

How much traffic can a roundabout handle?

Single-lane roundabouts can typically handle 20,000-26,000 vehicles per day and those with more than one lane can handle even greater traffic volumes. Due to the continuous flow of traffic, roundabouts generally have a greater capacity than signalized intersections, which also improves traffic flow and efficiency, especially during off-peak hours.

What is the cost of a roundabout compared to a signalized intersection?

There are many variables that make a direct cost comparison between a roundabout and a signalized intersection challenging. Numerous factors are evaluated when deciding the best control for an intersection and maintenance costs, land requirements, safety, operations and other factors all need to be considered.

Generally speaking, other than the initial construction the long-term cost of a roundabout is less than a signalized intersection as there are no ongoing hardware, maintenance or electrical costs.

There are also costs that are more difficult to measure. Roundabouts are considered safer than signalized intersections and when safety factors go up, the cost to society emotionally and physically goes down. At a four-way intersection there are at least 32 possible vehicle-to-vehicle conflicts. At a four-way roundabout there are only eight (8).

Looking specifically at the Westgrove Drive and McLeod Avenue roundabout, initial planning that was done in 2012 determined a multi-lane roundabout at that intersection would cost approximately $800,000, while the cost to install traffic signals would be approximately $250,000 with an additional $400,000 for required road improvements to widen and align roadways to allow for left turn lanes from the north and southbound lanes.

Additional costs associated with traffic signals would include yearly maintenance of the signals, as well as costs for electricity and other replacement or upgrade costs. A preliminary estimate puts this cost at approximately $15,000 per year not including major equipment replacement that may be necessary over time.