Today's question:

Our local Redevelopment Authority is proposing a change from an intersection with traffic lights to a roundabout at a key location in our town. Will a roundabout provide a safer way for pedestrians to move across our streets?
Photo by M.O. Stevens

Photo by M.O. Stevens

R. Moses Answers:

A roundabout can be both safer and more comfortable for pedestrians, but only if the design engineer knows how to integrate walkability into the roundabout. Here are some tips for properly equipping a roundabout for safe pedestrian crossings:

  1. In general, single-lane roundabouts are better and safer for pedestrians than two-lane.
  2. If one leg of your roundabout has particularly heavy exiting traffic volumes, it can be very hard for pedestrians to find a gap in traffic to cross. Motorists tend to be accelerating as they approach the exit leg, and as such, are less likely to stop to allow pedestrians to cross. This situation is more likely to occur at multi-lane roundabouts, and is rare at single-lane roundabouts.
  3. Care needs to be taken to make sure sight lines between motorists and pedestrians are maintained. It seems obvious, but sometimes the landscaping can become a bit much or get overgrown. Proper lighting at night helps, too.
  4. Pedestrian crosswalks should be located at least one car length back from the roadway and roundabout intersection. (However, this can increase the right of way size needed for construction which is not always possible.)
  5. Safety for blind/low-sighted people at roundabouts is a much more murky subject. Blind and low-sighted people tend to know when to cross the street at a signal based on the sound of traffic or lack thereof, or through the help of an audible pedestrian signal. When trying to cross a leg, especially an exit leg, of a busy roundabout, these audible cues are missing. At a busy roundabout, there are constant sounds of circulating traffic within the roundabout, and it is very difficult to tell if an approaching vehicle will exit the leg you wish to cross, or will continue circulating within the roundabout. As a result of this issue, the U.S. Access Board has recommended that all multi-lane roundabouts include pedestrian signals (HAWK signals) at each pedestrian crossing. If the pedestrian and vehicular volumes are heavy at your particular intersection, the presence and frequent use of the pedestrian signals may significantly reduce the vehicular capacity of your roundabout, possibly making signalization a better option. 
  6. While roundabouts can slow traffic making it safer for pedestrians, many drivers and pedestrians are not familiar or comfortable with them which causes confusion. Never a good thing for drivers or pedestrians. Americans need to be become more informed about how to use a roundabout safely and correctly.

In short, a roundabout can provide good, safe crossing opportunities for pedestrians, but only if engineers have pedestrians and bicyclists in mind when they design the roundabout, and only if drivers use them properly.

How would you respond to this question? Jump in with your answers in the comments!

Note: R. Moses is not meant to be professional engineering advice nor should be relied upon as such. Consult your own technical professional before proceeding with your own project.


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(Top graphic by Matthias Leyrer)


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