How To Conduct A Credible Bike Safety Study

Readers of Re-Imagine Menlo Park know how unhappy I am with the poor quality bike safety analysis produced so far by current The El Camino Real Corridor Study. After more than a year we have illustrations of possible bike lanes and bike paths on this primary vehicle artery (= highway) but no comprehensive treatment of the convenience and safety issues associated with these two options. You can read my recent letter to the city and city commissions about my concerns.

Bike safety is measurable and there are well-accepted metrics. So there is no need to rely on anecdotes, common perceptions or personal hunches. Here is an example of the nature of effort that is required in Menlo Park.

Route Infrastructure and the Risk of Injuries to Bicyclists: A Case-Crossover Study

Kay Teschke, Melody Monro, and Hui Shen are with the School of Population and Public Health, University of British Columbia, Vancouver, Canada. M. Anne Harris is with the Occupational Cancer Research Centre, Toronto, Canada. Conor C. O. Reynolds is with the Liu Institute, University of British Columbia. Meghan Winters is with the Faculty of Health Sciences, Simon Fraser University, Burnaby, Canada. Shelina Babul is with the BC Injury Research and Prevention Unit, Vancouver, Canada. Mary Chipman, Michael D. Cusimano, and Lee Vernich are with the School of Public Health, University of Toronto, Toronto, Canada. Jeff R. Brubacher and Garth Hunte are with the Department of Emergency Medicine, University of British Columbia. Steven M. Friedman is with the Emergency Department, University Health Network, Toronto, Canada. Peter A. Cripton is with the Department of Mechanical Engineering, University of British Columbia.

Objectives. We compared cycling injury risks of 14 route types and other route infrastructure features.

Methods. We recruited 690 city residents injured while cycling in Toronto or Vancouver, Canada. A case-crossover design compared route infrastructure at each injury site to that of a randomly selected control site from the same trip.

Results. Of 14 route types, cycle tracks had the lowest risk (adjusted odds ratio [OR] = 0.11; 95% confidence interval [CI] = 0.02, 0.54), about one ninth the risk of the reference: major streets with parked cars and no bike infrastructure. Risks on major streets were lower without parked cars (adjusted OR = 0.63; 95% CI = 0.41, 0.96) and with bike lanes (adjusted OR = 0.54; 95% CI = 0.29, 1.01). Local streets also had lower risks (adjusted OR = 0.51; 95% CI = 0.31, 0.84). Other infrastructure characteristics were associated with increased risks: streetcar or train tracks (adjusted OR = 3.0; 95% CI = 1.8, 5.1), downhill grades (adjusted OR = 2.3; 95% CI = 1.7, 3.1), and construction (adjusted OR = 1.9; 95% CI = 1.3, 2.9).

Conclusions. The lower risks on quiet streets and with bike-specific infrastructure along busy streets support the route-design approach used in many northern European countries. Transportation infrastructure with lower bicycling injury risks merits public health support to reduce injuries and promote cycling.

Read The Complete Study

A personal note: This study did not evaluate a busy highway like ECR and I expect the accident rate for ECR would be higher than a typical urban street as there are many more public driveways per mile, dangerous places where bikes and vehicles frequently cross paths.

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