Most research on cyclist safety is focused on bicycle-motor vehicle crashes. Only a few studies address single-bicycle crashes (i.e. a fall or obstacle collision), in spite of the fact that most cyclists admitted to hospitals are single-bicycle crash victims. This study developed a categorization of single-bicycle crash types. A draft categorization was developed based on the scarce literature that is available and theory on bicycle dynamics. This categorization was tested using a questionnaire study that was conducted in the Netherlands among bicycle crash victims treated at an Emergency Care Department. The questionnaire contained open questions about the crash and closed questions on possible direct causes, crash characteristics, and circumstances. The results indicate that about half of all single-bicycle crashes are related to infrastructure: the cyclist collided with an obstacle (1ai), rode off the road (1aii), the bicycle skidded due to a slippery road surface (1bi), or the rider was unable to stabilize the bicycle or stay on the bike because of an uneven road surface (1bii). The first two categories happen due to the cyclist inadvertently taking a dangerous riding line, while the last two happen under more direct influence of the road surface conditions. Other types related to the cyclist are loss of control at low speed (2a), due to forces on the front wheel (2b), or poor or risky riding behaviour (2c). Bicycle defects (3) contribute to a small group of crashes. Finally, some cyclists fall because of an external force such as a gust of wind (4). The study provides per crash type statistics on victims and circumstances. (Author/publisher)
Abstract