Now allowed: the tech that separates bikes and cars without a drop of paint

January 02, 2014

Michael Andersen, Green Lane Project staff writer


New York City's Ninth Avenue bike traffic signal. Photo: Kyle Gradinger/BCGP

There's a powerful consensus building that protected bike lanes are the next big step for U.S. bike infrastructure, but physical barriers aren't the only way to separate cars from bikes.

You can also separate cars and bikes with time.

That's what dedicated bike traffic signals are all about. They give bikes a head start at busy intersections where there's a risk of right-turn conflicts. They turn one lane of a one-way downtown street to a two-way bike thoroughfare. They let bikes cross a busy street midblock, or even diagonally across a key intersection. They reduce bicycle crash rates by up to 45 percent.

And as of Dec. 24, they no longer require a $20,000 engineering study to install.

As predicted last month by Streetsblog, the most influential American traffic signal organization has just endorsed the bike traffic signal for general, non-experimental use. Here's one in action, in Cambridge, Mass.:

The relevant memo from Federal Highway Administration Associate Administrator Jeffrey Lindley said the engineering pros behind Manual of Uniform Traffic Control Devices have determined that bie-specific traffic signals are safe enough for agencies to build almost anywhere they see fit, as long as they first get a general OK from the federal government.

Until now, the signals were allowed only on an experimental basis, a procedure that Peter Koonce, manager of the traffic signals division for the City of Portland, said requires a 10-page application plus a professional before-and-after analysis for each individual signal project.

"It's a great step," said Koonce, whose city has since 1994 installed 17 signals designed specifically for people on bikes. "it's a hurdle that agencies won't have."

Koonce said bike-specific signals go hand-in-hand with the spread of protected bike lane projects because, like physical separation of bike and auto traffic, they draw a clear line between different types of road users.


The many flavors of bike signals. Image: FHWA.

There are a few possible uses for bike-specific signals, though, that are specifically called out as not part of the new interim approval:

  • Pedestrian hybrid beacons, sometimes known as HAWK beacons, aren't generally allowed. These can be useful for letting bikes cross a busy street midblock, or using a low-traffic street such as a neighborhood greenway. These have already been endorsed by the more city-oriented NACTO guide.
  • Shared lanes. The new rule doesn't generally allow bike-specific signals when the only bike infrastructure on a street is a painted sharrow.
  • "Scramble" phases. A signal phase that freezes auto and pedestrian movement while people on bikes can head in every direction isn't generally allowed.

Lindley's memo didn't offer any explanation for these exceptions, so it's not clear what the chances currently are for advancing these ideas. Cities can, presumably, continue to apply for "experimental" uses of these tricks on a case-by-case basis.

As we wrote in November, auto-oriented traffic signals are a big obstacle to people on bikes. Even in cities where signals are set up to detect bicycles, half of riders don't know how to trigger them.

Dedicated bike stop lights, by contrast, don't only make intersections safer. As Lindley's memo notes, they make people on bikes more likely to follow the rules — because the infrastructure is actually working for them.

The Green Lane Project is a PeopleForBikes program that helps U.S. cities build better bike lanes to create low-stress streets. You can follow us on Twitter or Facebook or sign up for our weekly news digest about protected bike lanes. Story tip? Write michael@peopleforbikes.org.

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