In this study underlying mechanisms of the Safety in Numbers (SIN) effect in cyclists were studied. The SIN effect implies that with a higher number of cyclists (as well as pedestrians), their relative injury risks becomes lower. Conflicts between cyclists and cars as well as violations (running through red) were observed in two countries: Norway and Denmark. In Norway, the cyclist share is considerably lower than in Denmark. By comparing two intersections in countries in which the cyclist-share significantly differ, as well as having a more or less comparable infrastructure, it was possible to explore the ‘long-term SIN effect’ Interactions between car drivers and cyclists. The finding that the proportion of conflicts observed in Denmark is lower than the proportion of conflicts observed in Norway, independent of the season, suggests a long-term SIN effect. That is, cyclists and car-drivers have developed safer interaction-patterns. In Norway the number of cyclist dramatically increase during summer. By studying the same location during spring (April: lower cyclist share) and summer (June: higher cyclist share), short-term SIN effects could be studied. No significance differences appeared in Norway between April and June. These findings suggest that there is no short term change in car drivers expectancies of meeting a bicyclist with increasing numbers of bicyclists. However, these findings should be interpreted with some caution. For now we only have conflict data for one intersection in each country. In order to verify this, more data are needed from several intersections. The observed share of cyclists going through red was in general higher at the Norwegian intersection than at the Danish intersection. This different behaviour of Norwegian cyclists either suggests that these individuals are different (in ‘mentality’) than Danish cyclists, or that their lower presence and fewer cycling facilities ‘forces’ them to be in general somewhat more ‘daring’. (Author/publisher)
Samenvatting