In the Netherlands, the bicycle is a popular means of transport. One of the benefits of cycling is improved health due to more physical activity. However, cycling also causes a health burden due to the many cycling accidents in the Netherlands. The share of single bicycle accidents, where no collision with another road user is involved, has increased over the past years. In 2000 only 10% of all bicycle accidents were single bicycle accidents, while in 2018 this increased to 35%. One of the potential causes for single bicycle accidents is narrow bicycle paths. This research focussed on the influence of the bicycle path width of narrow bidirectional bicycle paths on steering behaviour, which can support a discussion on the required minimum width for bicycle paths in the guidelines. A controlled experiment is conducted to collect data of steering behaviour variables on different bicycle path widths while controlling other influencing factors. The results of the experiment show that cyclists cycle significantly closer to the path edge on narrower bicycle paths (55.6 centimeter on a 2-meter wide path and 37 centimeter on a 1-meter wide path), while there are no differences in average steering angle. An oncoming cyclist, which is in the experiment represented by a parked bicycle, forces cyclists to cycle even closer to the path edge, which makes the minimum distance to the path edge smaller. The minimum distance to the path edge becomes 15.1 centimeter on a 1.5-meter wide path. This smaller distance to the path edge increases the risk of riding off the path, which makes the narrower paths less safe. A questionnaire was used to examine the perception of the different path widths. The perceived safety of cyclists decreased on narrower bicycle paths. A 2-meter wide bidirectional bicycle path is considered safe to pass others by all participants, but on a 1.5-meter wide path this is only considered safe by half of the participants. The main research question was “What is the influence of the width of bidirectional bicycle paths on cyclists’ steering behaviour?”. It can be concluded that lateral position is related to the width of bidirectional bicycle paths, while steering angle rotation is not related to the width of bicycle paths. The results of the experiment are transferable to real-life traffic conditions, but do not include the variety in infrastructural conditions, cyclist ages and bicycle types. These varieties in real-life traffic conditions might increase the required bicycle path width.

Cycling is one of the main transport modes in the Netherlands and the total number of bicycles and the total cycling distances are still rising. Although this seems a positive development, the number of seriously injured cyclists due to bicycle crashes without motor vehicles increased rapidly in recent years. Within these crashes the infrastructure seems to play an important role and research towards the contribution of infrastructure characteristics to bicycle crashes without motor vehicles is needed because this is limited and especially research on more detailed infrastructure characteristics (e.g. bicycle path width) has not been done yet. This study aims to fill in parts of the knowledge gap between the safety problem and the lack of research done on the contribution of infrastructure characteristics. This study was done by using data from a survey held by VeiligheidNL. In total, 3146 cyclists that were treated at an emergency department responded to the survey and provided information on the crash location and the trip origin. A case-control method was applied in this study which compared infrastructure characteristics of case (crash) and control locations (no crash). The control locations were selected from the route of a bicycle crash victim. The design of the method included basic steps for the selection of the controls and four measures to lower the bias in the method and increasing the statistical power of the results. With the application of the case-control method to the data several results were found: First, the width of streets contributes to riding off the road crashes and handlebar collisions, whereas the width of bicycle paths next to bollards contributes to crashes with these objects. Secondly, the presence of intersections decreases the likelihood of kerb collisions. Thirdly, two-directional bicycle paths are more likely to induce bicycle-bicycle crashes and they possibly induce more severe crashes because frontal collisions were found more severe than same direction bicycle-bicycle crashes. And finally, the placement of bollards increases the severity of the injuries caused by the corresponding crashes. These findings could be used to further increase the quality of bicycle design guidelines such that future bicycle infrastructure could be designed safer.