Case-control study of fatal bicycle crashes in peri-urban areas of Delhi

There is a lack of evidence on interventions to improve the safety of cycling use in low- and middle-income countries. We investigated the impact of road design and traffic characteristics on the fatality risk of bicyclists.

Our study population is the road sites in the peri-urban areas of New Delhi, India. We used a retrospective, population-based case-control study design. We identified 50 case sites (road locations) where a fatal cycle crash had occurred over a 3-year period. For control sites, we intercepted and interviewed three cyclists at each case site, mapped their route to the crash location using Google Maps and selected one random location on each of those routes as controls. We recorded traffic and road design characteristics at the case and control sites. We used a logistic regression model to estimate ORs of site characteristics.

We found a strong effect of the presence of U-turns on the likelihood of a bicycle fatality, with an OR of 4.4 (95% CI 1.8, 11.5). This effect is robust against multiple sensitivity analyses. We found that the volume of cars is associated with an increased likelihood and that of motorcycles with a reduced likelihood of bicycle fatalities.

Our results indicate that the presence of U-turns is a strong risk factor for bicycle fatalities in Delhi. Given the strong evidence of their impact on the safety of bicyclists, their construction should be discontinued in zones of high bicycle presence.