Cycling Safety Positive Feedback Loop

Assuming cyclists have “safety in numbers,” the real question I posed in my last post is how can St. Paul or Minneapolis (or Anyplace, Minnesota) get more people on bikes?

The best way spur cycling is to make cycling appear safer. This recipe has many ingredients, but the most critical is giving users what they perceive as important: better protection from cars.

Is bicycle only infrastructure a golden ticket to such? Not necessarily. A burgeoning research base is forming around this issue (see, for example, exemplary studies[1],[2],[3]), however, to date it fails to provide divine inspiration. Advocates are quick to focus attention on ‘hot-spot’ maps depicting the number of crashes. Or they quickly dig out the most recent study showing how a new facility on a street lowered crash rates. But how well do these examples stack up to the balance of the literature? More than a few robust studies show bike facilities contribute to crashes.

The literature on cycling safety is vast, complicated to sort, and context dependent. The analysis of the 2,973 bicyclist-motorist crashes in Minneapolis found that bicycle crashes are complex and lack a single contributing factor. Likewise, studies relating crashes to facilities are often shaky on three accounts:

(1) Evidence relies on crashes as outcomes and fails to capture near-misses or other safety indicators. Bicycle crashes with cars are an infrequent occurrence among an infrequent activity. Even less is known about bicycle-only crashes (with stationary objects), crashes with other pedestrians or bicyclists or “looked but did not see” type interactions; municipalities don’t collect this data.

(2) Measuring and comparing cycling treatments varies by context—by culture, by type of facility, and by its location in the network. Despite accepted terminology[4], a “protected bicycle lane” differs from the next. Knowing how a studied facility fits into other network issues is similarly troubling.

(3) Any study needs to control for the number of cyclists at risk (i.e., exposure). Lacking a robust accounting of this dimension, a study is all but useless from the perspective of explaining safety risk[5].

Other issues always get in the way. Were speeds controlled? Was bicycle education routinely provided? How well did the study control for the experience of cyclists, socio-demographics, season or time of day factors? Addressing confounding explanations is a challenge that exists in all fields. However in cycling studies the challenge is heightened. Bicycle crashes are usually secondary data, confounders are often unavailable, and proxies are unclear. Furthermore, bicycle crashes involve pain, injury, and sometimes death. Cyclists don’t want to hear, “it depends”; they prefer straightforward and positive results.

But the best we know is that bicycle facilities (e.g. on-road bike routes, on-road marked bike lanes, and off-road bike paths) in some places appears to help reduce the risk of crashes, relative to cycling on the road with motorized traffic road[6]. This statement has caveats that are embedded in the context. Facility quality and context are paramount in understanding how people behave and who uses it.

maslow_needs_hierarchyGiven this unstable landscape, what is the strongest rationale to get more people on bikes and increase safety? The best line of reason is derived from our basic instincts as humans: a longing for safe environs. In his hierarchy of basic human needs[7], the sociologist Maslow placed safety just after physiological needs (e.g., breathing, food, and water). Safety desires influence behavior; most people at least perceive places with good cycling facilities to be safer.

It is easy to turn to hoards of anecdotes and personal observations: “It’s too dangerous on that street; there’s no bike path,” or “I’ll never bike there; the cars drive too fast and too close.” Such ‘anecdata’ are less than satisfying. These desires, however, are reflected in robust surveys of cyclists’ preferences, all of which point in the same direction: (1) safety features can be used as motivators to bike[8],[9],[10] and (2) existing cyclists prefer to ride where there are facilities[11],[12],[13]. People routinely report feeling safer with various types of facilities; generally, they want more separation from traffic rather than less[14]. Perception is reality and perceptions usually correspond well with observed behavior[15].

If residents perceive their cycling to be safer, they are more likely to bicycle and bicycle more often, which has the added benefit of increased safety through safety in numbers. Given this tautological reasoning, good bicycle facilities are the intervening element to initiate the “cycling safety positive feedback loop.”

[Thanks much to Meghan Winters, Krista Nordback, and Rebecca Sanders who provided valuable insights, guidance, and recommendations; any errors interpreting the balance of the literature are of course mine]

[1] Teschke K, Harris MA, Reynolds CCO, Winters M, Chipman M, Cripton PA, Cusimano MD, Babul S, Brubacher J, Chisholm D, Hunte G, Friedman S, Monro M, Vernich, Shen H.  Bicyclists’ Injuries and the Cycling Environment: The impact of route infrastructure. American Journal of Public Health. 2012; 102(12); 2336-2343.

[2] Harris MA, Reynolds CCO, Winters M, Cripton PA, Shen H.  Chipman M, Cusimano MD, Babul S, Brubacher J, Hunte G, Friedman S, Monro M, Vernich, Teschke K.  Bicyclists’ Injuries and the Cycling Environment: Comparing the effects of infrastructure on cycling safety at intersections and non-intersections. Injury Prevention.

[3] Lusk, A, Morency, P, Miranda-Moreno, L, Willett, W, Dennerlein, J. (2013) “Bicycle Guidelines and Crash Rates on Cycle Tracks in the United States.” American Journal of Public Health

[4] See, for example, “European Cycling Lexicon” (published by the European Economic and Social Committee at the Vélocity 2009 conference in Brussels), describing and depicting key cycling facilities in all 23 official European languages.

[5] The best account of the ability of different studies to do this is described on page 16 of [Conor CO Reynolds, M Anne Harris, Kay Teschke, Peter A Cripton, and Meghan Winters. The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature (2009). Environmental Health 8:47.] where studies may adjust for traffic volumes, cycling trip volumes or other.

[6] Conor CO Reynolds, M Anne Harris, Kay Teschke, Peter A Cripton, and Meghan Winters. The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature (2009). Environmental Health 8:47.

[7] Maslow, A.H. (1943). A theory of human motivation. Psychological Review, 50(4), 370–96.

[8] Winters M, Davidson G, Kao D, Teschke K. Motivators and deterrents of bicycling: comparing influences on decisions to ride. Transportation. 2011; 38(1): 153-168

[9] Winters M, Teschke K. Route preferences among adults in the near market for bicycling: Findings of the Cycling in Cities Study. American Journal of Health Promotion 2010; 25 (1): 40-47.

[10] Jennifer Dill and Kim Voros (2007). Factors Affecting Bicycling Demand Initial Survey Findings from the Portland, Oregon, Region. Transportation Research Record: Journal of the Transportation Research Board,No. 2031, Transportation Research Board of the National Academies, Washington, D.C., 2007, pp. 9–17. DOI: 10.3141/2031-02

[11] Winters M, Teschke K, Grant M, Setton EM, Brauer M. How far out of the way will we travel? Built environment influences on route selection for bicycle and car travel. Transportation Research Record. 2010; 2190: 1-10.

[12] Joseph Broach, Jennifer Dill, and John Gliebe, “Where Do Cyclists’ Ride? A Route Choice Model Developed with Revealed Preference GPS Data,” Transportation Research-Part A, 46: 1730–1740, 2012.

[13] Jennifer Dill, “Bicycling for Transportation and Health: The Role of Infrastructure,” Journal of Public Health Policy, 30 (SI): 95-110, 2009.

[14] Rebecca L. Sanders (2014). Roadway Design Preferences Among Drivers and Bicyclists in the Bay Area. To be presented at TRB 2014.

[15] Safe Cycling: How Do Risk Perceptions Compare With Observed Risk? Meghan Winters, Shelina Babul, PhD, H.J.E.H. (Jack) Becker, MBA, Jeffrey R. Brubacher, MD, MSc, Mary Chipman, Peter Cripton, Michael D. Cusimano, Steven M. Friedman, M. Anne Harris, Garth Hunte, Melody Monro, Conor C.O. Reynolds, Hui Shen, Kay Teschke.

Kevin Krizek

About Kevin Krizek

Kevin J. Krizek is Transport Professor, Programs of Environmental Design and Environmental Studies at the University of Colorado Boulder. He was a 2013 fellow of the Leopold Leadership Program and received a 2013 U.S.-Italy Fulbright Scholarship to the University of Bologna (Italy). He is currently a visiting professor of "Cycling in Changing Urban Regions" in the School of Management Science at Radboud University in the Netherlands. Kevin blogs at Vehicle for a Small Planet and can be found @KevinJKrizek . Prior to moving to Colorado, he lived in Minneapolis and St. Paul and was an Associate Professor at the Humphrey Institute of Public Affairs at the University of Minnesota.