Wider view over bicycle accidents: Complementing and extending bicycle accident statistics in urban areas using surveys

City traffic planners are striving to adapt their infrastructure to not only increase the number of cyclists but also to ensure that city cycling is both enjoyable and safe. In Switzerland and in many other countries, it is suspected that only one of ten bicycle accidents is reported to the police [ 1-5]. Only knowing about 10% of the accidents, on top of the fact that there are luckily not many accidents from a statistical perspective, casts doubt about where efforts should be made to improve cycling infrastructure, and how effective the actions taken actually are. To deal with this lack of data, this paper proposes to use surveys of cyclists besides police records to obtain a more complete picture of the number and location of cycling accidents, including the ones not reported to police, and the locations that cyclists perceive as dangerous. The combination of survey and police reported data gives a considerably different and more complete impression of where there is potential to improve cycling infrastructure, when compared to that obtained using only police reported accidents. This work expounds how the survey responses about hazard perception and unreported accidents help provide a more complete overview of the accident potential of the existing cycling network and how they form a base of immensely useful inputs for planning improvement