Traffic and Safety Information

Roundabouts keep traffic rolling – more safely.

As a car enters a roundabout, it is not required to come to a complete stop to proceed through the intersection like a traditional all-way stop intersection. By yielding at the entry rather than stopping and waiting for a green light, queuing and delay are significantly reduced – typically by 10 to 12 seconds per vehicle. A reduction in delay corresponds to a decrease in fuel consumption and air pollution. Intersections with a high volume of left turns are better handled by a roundabout than a multi-phased traffic signal because turn lanes and signals are not required and traffic is allowed to continuously flow through the roundabout while yielding for pedestrians and other vehicles.

In addition to reducing traffic delays, roundabouts have been shown to reduce fatal and injury accidents. The reduction in accidents is due to the slower speeds and reduced number of potential vehicle conflict points. Two studies involving six intersections were performed by the Federal Highway Administration in 2009. The results below showed the reduction in accidents per year:

  • All accidents reduced by 70%
  • Injury accidents reduced by 88%
  • Fatal Accidents reduced by 100%

For the design of a new roundabout, safety can be optimized not only by relying on recorded past performance of roundabouts in general, but also by applying all design knowledge proven to impact safety.