http://www.citylab.com/commute/2014/06/protected-bike-lanes-arent-just-safer -they-can-also-increase-cycling/371958/

Not all bike lanes are created equal. A line in the pavement dividing cars from cyclists is nice, but it doesn't provide nearly the comfort of a protected bike lane - a track separated from vehicle traffic by a row of parked cars, or a curb, or at least a line of flexible posts. Cyclists who use protected lanes say they feel safer, and some studies show they truly are safer, with their risk of injury cut in half http://www.citylab.com/commute/2012/10/dedicated-bike-lanes-can-cut-cycling -injuries-half/3654/ .

That's great for committed riders and public health more broadly. But what about city residents who don't already ride a bike, perhaps due to safety fears? After all, it stands to reason that cities invest in bike infrastructure not just to secure the existing rider population, but to expand it. So is the assurance of a protected bike lane enough to make a cyclist of those who might otherwise choose another transportation mode?

New research suggests that, to a modest extent, the answer is yes. Today a study team http://otrec.us/project/583 led by Christopher Monsere of Portland State University released a thorough analysis of new protected bike lanes in five major U.S. cities. The researchers videotaped the new lanes, conducted local surveys, and gathered data on cycling trends to get a full picture of life in these new corridors - comparing what they found to rider habits before the protected lanes were installed. They found that ridership increased anywhere from 21 to 171 percent, with about 10 percent of new riders drawn from other modes.

The analysis focused on new bike facilities along eight city streets: Barton Springs, Bluebonnet, and Rio Grande in Austin; Dearborn and Milwaukee in Chicago; Multnomah in Portland, Oregon; Oak and Fell (a street couplet) in San Francisco; and L Street in Washington, D.C. Some of the corridors had an unprotected bike lane before the study, others had nothing at all.

While the research looked at a range of measures, including safety and lane design, we'll focus on ridership here. Cycling rates rose on the new lanes across the board. The following chart, prepared by the researchers, shows street ridership counts based on an average of city data and video analysis. The biggest gains - with ridership more than doubling - occurred on two streets converted into two-way lanes.

That's to be expected, but the fact that even streets with an existing bike lane saw a spike in ridership shows just how attractive protected lanes are:

http://cdn.theatlantic.com/newsroom/img/posts/2014/06/protected_lane_chart/7 f1810311.jpgVia Monsere et al (2014)

Those results are impressive, but on their own they have limited meaning, since cycling in these cities is on the rise everywhere. A better baseline comparison comes by placing ridership in the new corridors against general trends across the city. Here, too, the protected lanes performed well. Ridership in the new lanes beat the city average along all but one street - and on that street (Milwaukee) it matched the average.

http://cdn.theatlantic.com/newsroom/img/posts/2014/06/Change_in_Ridership_Av erage_Increase_Protected_Lanes_Citywide_Increase_chartbuilder/6600db3f3.pngC ityLab

The key is not just whether the protected lanes attract more riders, but whether they attract new riders. In surveys, the researchers found that across all five cities, 65 percent of riders would have gone by bike along this street anyway, and that another 24 percent, evidently comforted by the protected lane, would have traveled by bike but gone a different route. Critically, 10 percent of the new riders would have taken another (unspecified) mode - a share that reached 21 percent along the Dearborn corridor in Chicago:

http://cdn.theatlantic.com/newsroom/img/posts/2014/06/Shift_in_Ridership_Fro m_Other_Modes_New_Mode_chartbuilder/e2bb9ade5.pngCityLab (data for Bluebonnet not available)

So protected bike lanes do seem to serve the double purpose of improving rider safety while also inspiring people to ride in the first place. There are some key caveats to keep in mind: the big percentage swings reflect relatively small total numbers, often in the tens of riders, and it's unknown how many riders made a true shift from driving (as opposed to from other transit modes). These are also five cities with growing bike cultures: it's unclear how well protected lanes would perform in places where cycling isn't already a rising subculture.

But there's fewer of those places http://www.citylab.com/commute/2014/05/rise-bicycling-smaller-and-midsize-u s-cities/9059/ every day, which is precisely the point.