Traffic conflicts and their contextual factors when riding conventional vs. electric bicycles

- E-bikes faster than conventional bicycles, leading to concerns about traffic safety.
- Investigation of traffic conflicts of e-bikes and bicycles with naturalistic data.
- Data of 80 riders gathered with instrumented bicycles over four weeks per rider.
- No differences in overall traffic conflict risk between the bicycle types.
- Increased risk of conflicts for e-bikes in the vicinity of intersections.

The prevalence of electric bicycles (e-bikes) has increased considerably in the past few years. Because of their potential to reach higher speeds than conventional bicycles, concerns have been raised about a possible increase in traffic conflicts and crashes. The goal of this study was to examine if there are differences between conventional cyclists and e-bike riders with regard to the probability to be involved in a traffic conflict. In addition, the circumstances under which conflicts occur were investigated to identify potential differences in risk dependent on contextual factors. Utilising the naturalistic cycling approach, the personal bicycles of 80 participants (31 conventional cyclists and 49 e-bike riders) were equipped with a data acquisition system that included two cameras and a speed sensor. Four weeks of “normal” cycling were recorded for each participant. The analysis showed no difference between bicycles and e-bikes with regard to their overall involvement in traffic conflicts, as well as for the role of most contextual factors. One notable exception were intersections, where the risk of being involved in a conflict was twice as high for e-bikes as for conventional bicycles. The speed immediately preceding a conflict was higher for riders of e-bikes compared to conventional bicycles, a pattern that was also found for mean speed. While the general safety concerns regarding e-bikes could not be confirmed, the finding that e-bike riders are somewhat more at risk around intersections shows that under specific circumstances, other road users might still need time to adapt to this relatively new type of vehicle.