Bicycle Safety at Intersections--A Before and After Study. Per Näsman, Center for Safety Research, KTH, Sweden
The building of new bicycle paths in the city of Gothenburg, Sweden, from 1993 and on gives a unique opportunity to use the methodology for before and after studies. The intervention to be studied is the effect of raising bicycle crossings to roughly the same level as the bicycle paths, in order to improve the bicycle safety by reducing the velocity of the motor vehicles and raise the drivers' attention. A before and after study includes an estimate of what the accident outcome would have been, had the intervention not been applied. We will explore different methods to estimate this outcome and evaluate the accuracy of the methods. We will also compensate for fluctuations in bicycle flow. In addition to data about traffic flows, accident data and results from interviews with experts, we are to include results from a questionnaire given to cyclists. This questionnaire will pinpoint the change in bicycle safety, due to the intervention, perceived by the cyclists.