Circular logic: What roundabouts mean for bike safety

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Photo by Mary F. Calvert for the New York Times

Bicycle enthusiasts and advocates often talk of importing infrastructure and ideas from European cities like Copenhagen and Amsterdam (guilty as charged), where the number of people on bikes dwarfs what the Seattle region has been able to accomplish so far.

What about a particular European infrastructure import?  The New York Times published a piece on Thursday about the roundabout: it’s prevalent in Europe (France has more than 30,000) but for U.S. drivers, it doesn’t seem to be love at first sight.

But as I read the piece, I recognized a similar story-line: people fear something new, something new happens, then people often like it.  Such is the case with rechannelizations or “road diets,” once the dust settles and the facts replace the hyperbole.  Surveys in the U.S. about roundabouts reflect a similar phenomenon: 34% support before construction, 57% after and then 69% a year later reports the Insurance Institute for Highway Safety (IIHS).

Of course there seems to be some contradictions in the NY Times reporting whether or not they actually work.  But that’s reporting.  I’ll put my money on the safety data.   Says WSDOT: they’re safer—with 90% fewer fatality crashes—and they’re cheaper.  Says the IIHS: they’re safer and more fuel-efficient.

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A bike roundabout in Koper, Slovenia.

But what about bikes and peds?  In the New York Times article and many others, I saw no reference.  I’ve been paying more attention to on-street circles of all size and type after having some difficulty with what I’ll call the “Seattle traffic calming circle” (neither a roundabout, nor really a traffic circle).  I was nearly run over by a minivan cutting left. (Illegal? Legal? That’s a different story.  But my quick take: they’re excellent traffic calming measures and work well for all users if people use them correctly.  Reducing speed and volume on streets is particularly beneficial to bikes.)

WSDOT has some handy information for bicyclists and pedestrians in navigating roundabouts (even this video), saying that they’re designed for better safety.  I watched skeptically and anxiously as three cute kids and a mom barely get across a sizeable roundabout.  While this roundabout in the video has a pedestrian refuge island and is set back from the roundabout (good!), crossing distance still seems a concern.

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I then tried to dig up associated research on any safety benefits for those on bike.  The verdict?  Safer for cars doesn’t always mean safer for bikes.  This article details some of the issues.  The USDOT chimes in.  A study in Davis, CA, raises concerns.  The Florida state DOT notes that bicycles are 15 times more likely than cars to have a crash at a roundabout.  And a Transportation Research Board paper from the National Roundabout Conference concludes that, while further research is needed, data suggest that roundabouts raise severe injury crashes for bicyclists.  Sure, you can build additional safety features on major road projects, but how effective can they be if speed and volumes are still high—and turning movements are hasty (I mean, who wants to do laps on a roundabout except for Chevy Chase in European Vacation?)

The two messages I hear are clear: first, roundabout concerns are context-dependent.  For instance, large multi-lane roundabouts (a far different beast from those Seattle traffic calming circles) can be really dangerous for bikes, as the Florida DOT learned (and as I remember from charging through many in large cities in Europe).  And second, while many safety treatments for cars often make roads safer for bikes, this is not always the case.  Whatever tools we use on the road, let’s make sure that they’re safer for everyone—especially for more vulnerable road users like those on bicycles and on foot.