As Protected Bike Lane Design Evolves, New Lessons Emerge

Dedicated bike signals in downtown Seattle mean that bikes and cars never have to mix on Second Avenue’s new protected lane. Photo: Green Lane Project

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Michael Andersen blogs for The Green Lane Project, a PeopleForBikes program that helps U.S. cities build better bike lanes to create low-stress streets.

Last year offered lots of case studies for those of us working to make the case for protected bike lanes. With the explosion of protected lanes in the United States, we have far more robust evidence — both anecdotal and quantitative — that they increase ridership, make streets safer, and benefit cities economically.

Here are some useful lessons on design from the cities pioneering the use of protected lanes:

1) People like dedicated bike signals much better than merging with a turn lane

Until the protected intersection takes off in the United States (more on that in a few days) there are two basic ways to handle the conflict between bikes that are going straight and cars that are about to turn. One way is more popular than the other.

The more common (but less popular) method is to direct both vehicles to merge into a combination turn lane/bike lane. The more popular option, which is rarely employed, is to use special traffic signals that force people in cars to stop turning while bikes are crossing.

As the chart above shows, most people biking tend to feel safe in both situations, but less confident riders — the ones protected bike lanes are supposed to appeal to — strongly prefer signalized separation, as seen on Chicago’s Dearborn Street, Seattle’s Second Avenue, and the Indianapolis Cultural Trail. (It’s no coincidence that these three ranked at the top of our “best new bike lanes” lists in 2013 and 2014.)

U.S. intersection design continues to develop, and “mixing zone” designs have been getting better. (Here’s what the best-performing mixing zone, at Fell and Broderick in San Francisco, looks like; compare that to the worst-performing, on L Street in Washington, DC.) In any case, engineers should remember that the whole point of protected bike lanes is to make biking feel safe for people who don’t already ride. Designs won’t work unless they achieve this.

2) When it comes to comfort, people say plastic posts are as good as curbs

For us on the Green Lane Project team, one of the biggest surprises of 2014 was that a bike lane separated from cars by a “2-3 foot buffer with plastic flexposts” makes riders feel more comfortable biking than anything else, with the exception of “planters separating the bikeway.”

The finding came from a survey of people riding in many different protected bike lanes around the country. (For this question, the people were looking at a series of renderings, which you can see on p. 146 of this PDF.) The finding was (like all three of these) deep within a landmark report released in early June by the National Institute for Transportation and Communities.

As anyone who's compared the costs of bike lane separation methods knows, a cast-in-place curb is much more expensive to install than a row of plastic posts. So this should be comforting news to cities that have, like Washington DC, Chicago and Pittsburgh, used flexposts to install physical separation as cheaply as possible.

The true downside of flexposts, as cities have also found, is that they're easily destroyed. After seeing its posts torn up last winter by plows and skidding drivers, Chicago sent crews out to temporarily remove the posts from the streets, to be reinstalled next spring. That's probably wise, but it only takes a few years of that before a city starts looking again at the cost of installing something more durable.

A more detailed federal study of this issue, probably with different methodology, is set to begin this year. We eagerly await the findings.

3) Most people like protected bike lanes. But some people hate them.

This chart isn’t news to anyone who has built a significant biking project. But it’s something officials need to be prepared for every time. Even in centrally located, multi-modal neighborhoods where most existing protected bike lanes were built, some residents are convinced that it hurts the neighborhood to dedicate any street space to anything other than cars. And bike lane skeptics may well be more passionate and noisy than proponents.

The lesson of this chart isn’t that we should live in fear of a vocal minority. It’s just a reminder that with any project as visible and meaningful as a protected bike lane, some people will see themselves as winners and others will see themselves as losers. And also that members of another group — about the same size as the self-identified winners — can be swung either way depending on their perception of why the project was built.

The ridership impacts of protected bike lanes prove they’re worth fighting for. But cities shouldn’t build them without being able to explain why a connected network of low-stress bike routes will make everyone a winner.

“It’s sort of like ripping that Band-Aid off really quick,” Pittsburgh Mayor Bill Peduto said in September about his plans to rapidly install a basic network of protected bike lanes in his first term. “We knew there was going to be this pushback, but we wanted to show [the new protected lane] and let people see it. That type of a reaction starts to dissipate and go down over time. That’s the tradeoff.”

As we’ll show in an upcoming post, 2014 was a very big year for protected lanes. But here in the United States, these designs are still in their infancy. We’re sure that 2015 will bring new findings that move this concept toward maturity, and we look forward to sharing them with you all year, right here.

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