The chair of road planning and operation initiated two research projects concerning the dynamics between right-turning vehicles and cyclists going straight ahead. It should be analyzed in what way the infrastructure and behavior from both road users influence the turning accident occurrence and how to reduce the conflict rate. The first project, initiated by the German Insurers Accident Research (UDV) as part of the German Insurance Association (GDV), was finalized in 2012 including right and left turning vehicles and cyclists driving straight ahead. The target of that research project was to give recommendations to improve safety of cycling infrastructure at intersections in built-up areas. The second project for the Federal Highway Research Institute (BASt) was finalized in 2014 and focused on the conflict between right-turning trucks and cyclists driving straight ahead. Both projects conclude in recommendations concerning measures for infrastructural changes, driver assistance systems and behavior change to improve the traffic safety for cyclists.

Both projects comprised a macroscopic and microscopic accident analysis, an infrastructure analysis and a behavioral observation of cyclists and vehicle drivers at intersections in order to identify types of infrastructure and behavior that provoke turning-off accidents. The second project included an extra behavioral observation of truck drivers in a driving simulator. Additionally, an analysis of turning assistant systems which can minimize the blind spot was implied to this project. The aim of this research project is to outline recommendations to improve the safety of cycling infrastructure at intersections and to evaluate the safety-benefit of driver assistant systems. Results of the accident analyses are that most accidents happen in motion when the cyclists arrive from behind and the vehicle drivers are busy with turning so they tend to oversee cyclists. Situations where the vehicle drivers and the cyclists start at the beginning of the green phase are nearly conflict-free.

Key recommendations are to improve the visibility between vehicles and cyclists for example by guiding the bicycle lane close to the carriageway and therefore improve the awareness of road users. The car drivers should look out for cyclist not only through mirror checking but also by directly looking over their shoulder. Last but not least electronic assistant systems could support the driver to recognize cyclists. Nevertheless, due to the behavior of cyclists and obstacles in the side areas it continues to be challenging to detect them reliably. At complicated and complex intersections with many cyclists it is therefore recommendable to use different signalizing phases.