There hasn’t been time yet for a thorough review of the new study of barrier-separated bikeways on streets now being touted by the bicycling-industry lobbying organization PeopleforBikes, though claims of lack of traffic conflicts on these bikeways fly in the face of the experience of actually riding in them, and the results of earlier studies. The saying on the sign below is pertinent. Update, July 1, 2014: a quick “review preview” is now available.
As is usual among advocates for such bikeways, PeopleforBikes uses the feelgood propaganda term “protected bike lanes” for them — though they are technically paths, not lanes, and are unprotected where most car-bike crashes happen, at intersections and driveways. PeopleforBikes cites three earlier studies as setting the stage for the new one, and offers a tepid acknowledgement of criticism of these studies, with a link to criticism of only one of them, along with an appeal to groupthink, and while reiterating the studies’ conclusions:
Three widely noticed Canadian studies, led by Harvard’s Ann Lusk, the University of British Columbia’s Kay Teschke and Ryerson University’s Anne Harris, 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 for underexamining the importance of intersections, where most bike-related conflicts arise.
The three Canadian studies which PeopleforBikes cites have been reviewed, in detail, and demolished.
The study Lusk, A. C., Furth, P. G., Morency, P., Miranda-Moreno, L. F., Willett, W. C., & Dennerlein, J. T. (2011). Risk of injury for bicycling on cycle tracks versus in the street. Injury prevention, 17(2), 131-135, claims a 28% lower crash rate for cycle tracks in Montreal, relative to comparison streets. Flaws of the study include describing stretches of paths in parks and away from streets as cycle tracks; including stretches which had not been built yet in the reported mileage; selecting a multi-lane comparison street 10 blocks away with heavy, faster traffic for comparison with a cycle track street which is small and has light, slow traffic, examining short stretches which end just short of busy intersections; giving the length of one of the paths as twice as long as it is, halving its reported crash rate, and neglecting injuries to pedestrians. A detailed rebuttal and a link to the study online may be found here. Another review reaches similar conclusions.
Teschke, K., Harris, M.A., Reynolds, C.C., Winters, M., Babul, S., Chipman, M., Cusimano, M.D., Brubacher, J.R., Hunte, G., Friedman, S.M., Monro, M., Shen, H., Vernich, L., & Cripton, P.A. (2012). Route infrastructure and the risk of injuries to bicyclists: a case-crossover ctudy. American journal of public health, 102(12), 2336-2343. has been reviewed and debunked by John Forester. The central problem is that the one facility described in the study as a cycle track and used for comparison with all the others is a bikeway on a long bridge separated by a Jersey barrier, with no cross traffic.
M Anne Harris, Conor C O Reynolds, Meghan Winters, Peter A Cripton, Hui Shen, Mary L Chipman, Michael D Cusimano, Shelina Babul, Jeffrey R Brubacher, Steven M Friedman, Garth Hunte, Melody Monro, Lee Vernich and Kay Teschke, Comparing the effects of infrastructure on bicycling injury at intersections and non-intersections using a case–crossover design, 19:5 303-310 doi:10.1136/injuryprev-2012-040561, has also been reviewed and demolished. The comments published on the Injury Prevention Web site are a condensed version of the ones published here and here. An explanation of how they came to be condensed is here. The authors oddly found bicycle-only paths in parks to be 17.6 times as dangerous as bicycle-only paths in (or adjacent to) streets. They find multi-use paths in parks to be 22.8 times as dangerous as bicycle-only paths in streets; and riding in the street to be 20 times as dangerous as riding in a bicycle-only path in the street. These results are bizarre and contradict those of numerous other studies.
Note that the authorship of these two studies overlaps.
Teschke gave a presentation at the 2012 Velo-City conference in Toronto. I have posted comments on this presentation. My review addresses the deficits in epidemiology as an approach to the study of traffic safety, and also, specifics of the presentation. The graphics for the presentation display the preposterous result from the Harris study that bicycle crashes were 2000% as high on streets without cycle tracks as on streets with them, although the study also reports that more than half of all the crashes did not involve a motor vehicle. There are other absurdities. Also, it is clear from the authors’ presentation at a conference that they do not understand the definition of a collision, or intentionally skewed their data by describing single-bike crashes as collisions.
The authors of these studies flaunt their academic credentials, which may look impressive except when noting their errors of methodology and selection of data. These are not unbiased researchers: they are avid promoters of separate bikeways on streets, and the bias shows.