The demographic change, the increasing number of pedelecs and the higher share of cycle traffic in several cities lead to a substantial change of cycling traffic volume, traffic composition and cycling speeds. In the future, especially in cities, increasing cycle traffic volumes and diverse cycling speeds are expected. The intention of the study was to determine if these recent development influence the amount of cycling accidents and which measures should be taken to increase cycle safety. For different forms of cycle facilities the study determined the influence of cycling traffic volume, cycling speeds and the age structure on the number, severity and types of accidents involving cyclists. The following main findings could be drawn from traffic counts, behavioral observations, speed measurements and accident analysis: * Compared to previous studies, the average cycling speeds have increased by about 1.5 km/h to about 18.2 km/h. * With increasing bicycle traffic volumes the sections with minor intersecting streets show an increasing number of cycling accidents and a higher share of accidents with serious personal injuries. Similar findings could not be obtained at signalized intersections. * Sections with a higher level of cycling speeds showed a shift to more accidents between vehicles moving along the same/ opposite way * Special safety problems, especially at cycle paths, exist due to wrong-way driving * Cyclists over 65 years have an about twice as high average accident risk compared to 25 to 65- year-old cyclists. Similar findings could not be obtained at signalized intersections. * Accidents involving older cyclists have a higher share of severe accidents at sections as well as at intersections * Sections with higher cycling speeds showed a slightly increased number of accidents. However, this influence is superimposed by the bicycle traffic volume. Sections with higher cycling speeds showed a higher share of accidents between vehicles moving along the same/ opposite way and accidents involving stationary vehicles. By developing six scenarios, possible future trends and their impact on cycle safety were estimated. S1: moderate short term increase in bicycle traffic volume S2-A: medium-term change in age structure S2-A-20: change in age structure and a moderate increase of bicycle traffic volume S2-A-20-V: moderate increase in bicycle traffic volume and a change in cycling speeds due to changes in age structure and new bicycle types S2-A-40: change in age structure and significant increase of bicycle traffic volume S2-A-40-V: significant increase of bicycle traffic volume and speeds. The calculations for the scenarios were based on the actual mix of guideline conform and defective bicycle facilities. The scenarios showed that the increasing number of cycle accidents with personal injuries at road sections, and even more the number of severe cycle accidents, is mainly due to the increase of bicycle traffic volume. Under the conditions of scenario S2-A-40-V, the number of bicycle accidents with personal injuries will be the double of today’s level — severe bicycle accidents will even increase by a factor of 2.4. Concerning the several forms of bicycle facilities, the highest increase of accidents are expected on cycle lanes and on lanes with mixed traffic of cars and bicycles; the lowest increase in bicycle accidents are expected at cycle paths. Similar findings could not be obtained at signalized intersections. However, due to the changes in age structure the share of severe accidents may rise to a level of 16 % of accidents with personal injuries. The recommendations of the study are based on the knowledge of today's bicycle traffic. By now, there are already cycle facilities with high bicycle traffic volume or cycling speeds and elderly cyclists are already particularly at high risk. The recommendations for the future cyclists are therefore relevant today and should be applied to counteract the increase of cycle accidents. Basically, common cycling facilities such as cycle paths, cycle lanes, lanes with mixed traffic and advisory cycle lanes are suitable facilities for the future. Because of their low average accident rate and their weak impact of bicycle traffic volume on cycle accidents, cycle tracks should - as far as infrastructural possible - be more used as an alternative to common cycling facilities. To reduce the particularly increasing accidents between vehicles moving along the same/ opposite way, speed limits of 30 km/h should be considered for lanes with mixed traffic. The widths of cycle paths should allow an overtaking among cyclists and thus reduce accidents among cyclists. At cycle lanes safety distances to parking cars are especially recommended. Considering the isolated effect of changing age structure (scenario S2-A) the increase of accidents caused by crossing roads, turning into or off the roads need special consideration at sections and intersections. At cycle paths these types of accidents need to be considered at driveways as well. In future, higher cycling speeds will increase accidents between vehicles moving along the same/ opposite way and accidents involving stationary vehicles even more. This emphasizes the need for sufficient widths of cycle paths and cycle lanes. Safety distances between traffic and parking cars should be considered at lanes with mixed traffic as well. Special groups of cyclists with higher average speeds - in particular young adults and users of pedelecs— should be sensitized to the specific speed-related risks. (Author/publisher)
Abstract