It's a sign of how new the modern protected bike lane http://www.peopleforbikes.org/green-lane-project/pages/protected-bike-lanes -101 is to the United States that we have known very little about them, scientifically speaking.
Most academic studies of modern protected lanes have relied on data from countries where culture, land use, street design and social behavior are dramatically different (the Netherlands, Denmark, Germany) or from Canada, which has led the North American protected lane revolution http://bikelanes.ca/on-urban-bike-infrastructure-canada-is-now-leading-the- way/ . Three widely noticed Canadian studies, led by Harvard's Ann Lusk http://injuryprevention.bmj.com/content/early/2011/02/02/ip.2010.028696.ful l.pdf+html , the University of British Columbia's Kay Teschke http://cyclingincities.spph.ubc.ca/injuries/the-bice-study/ and Ryerson University's Anne Harris http://injuryprevention.bmj.com/content/19/5/303.full , focused mostly on safety. And though all three concluded that protected bike lanes greatly improve bike safety (28 percent fewer injuries per mile compared to comparable streets with no bike infrastructure using Lusk's methodology, 90 percent fewer using Teschke's; in Harris's study, protected lanes reduced intersection risk by about 75 percent), they've drawn some thoughtful criticism http://injuryprevention.bmj.com/content/19/5/303.full/reply#injuryprev_el_1 0126 for underexamining the importance of intersections, where most bike-related conflicts arise.
Today, Portland State University's National Institute of Transportation and Communities http://otrec.us/NITC released its voluminous findings http://ppms.otrec.us/media/project_files/NITC-RR-583_ProtectedLanes_FinalRe portb.pdf from a wide-ranging study of protected bike lane intersections in five U.S. cities. It's based on 204 hours of video footage that captured the movement patterns of 16,000 people on bicycles and 20,000 turning cars; on 2,301 surveys with people who live near the projects; and on 1,111 surveys of people using the protected lanes.
"This has never been done on this scale - having five cities and a number of different sites being done at the same time," NITC spokesman Justin Carinci said in an interview Monday. "The number of hours of video review is unprecedented. But the perceptions piece is really the most definitive of it: This is a big enough sample that we could say for each of the (projects), people feel safe riding them. People say we should have more of them."
The new study was co-funded by the U.S. Department of Transportation, the Summit Foundation http://summitfdn.org/ and PeopleForBikes. The team was led by PSU's Christopher Monsere, Jennifer Dill, Kelly Clifton and Nathan McNeil. You can download the whole report http://ppms.otrec.us/media/project_files/NITC-RR-583_ProtectedLanes_FinalRe portb.pdf immediately, but if you want the Cliff's Notes, we'll be digging into this huge study here on the Green Lane Project blog one angle at a time, all this week:
* Tuesday: How protected lanes affect ridership http://www.peopleforbikes.org/blog/entry/everywhere-they-appear-protected-b ike-lanes-seem-to-attract-riders * Wednesday: Protected bike lanes and intersection safety * Thursday: What protected lanes can't do * Friday: Finally, scientific evidence that changes to auto parking make people crazy
Stay tuned - for those of us who see the potential for bikes to improve cities, the findings are exciting and the notes of caution are useful. We'll be here all week.