Analysis of interactions between crossing cyclists at intersections based on trajectory data

Cyclists have the option of crossing at various streets and intersections, with or without traffic lights, and with or without a bicycle path.Frequently, the traffic regulations pertaining to cross on vehicle lanes are clearly stipulated for cyclists as well.However, in Germany, the situation regarding bicycle paths is often more complex.In Germany, a total of 32% (n = 1565) of all bicycle-bicycle accidents in 2023 (n = 4867) were accidents involving injuries when cyclists crossed paths, resulting in 3 deaths [7].Due to the paucity of research on intersection behaviour, it is imperative to ascertain how cyclists behave when crossing on a daily basis and whether critical interactions frequently occur.This publication presents the research methodology and descriptive results of two traffic observations and a related survey.One observation was conducted at a signalised urban intersection with separated bicycle and footpaths, and the other one at a non-signalled intersection without a separated bicycle path.Both locations are in Braunschweig, Germany.At these intersections, the trajectories of road users were recorded by using camera systems and subsequently analysed with the aim of identifying interactions between crossing cyclists.It appeared that there was direct crossing of the path or a merging of the two bicycle paths.At the main measurement location, a total of 171 h of video data were analysed.Of these, 120 interactions were recorded at a PET ranging from -3 to 3 s.A low PET is often considered a safety critical indicator of an interaction.2.2% of interactions occurred at a PET between -1 and 1 s, suggesting an elevated possibility for conflict.The results indicate that, irrespective of the presence of traffic lights on the bicycle path or the absence thereof, approximately only 50% of cyclists yield to other cyclists, which have the right-of-way.A survey conducted as part of this study revealed that many cyclists are unaware of the rules that govern their use of bicycle paths.A second measurement location without a bicycle path also shows that around 50% of cyclists give way.Due to the width of the road, distances and PET values are greater, but speeds are also higher.The study highlights the serious potential for cyclist conflicts at intersections and the need to develop mitigating measures like education.