This paper reports the results of accident analyses in six German cities, performed to investigate the effects of area-wide traffic calming measures on traffic safety. The analyses were based on the records of the police authorities, where the accidents were registered; their files include all accidents known to the police. Each accident was evaluated according to 29 features about: (1) the type of involvement in the accident; (2) the accident's causes and consequences; (3) the local situation at the time of the accident. The data were analysed using various statistical methods. In Berlin-Charlottenburg, traffic calming measures have led to a considerable reduction in both the number and the severity of road accidents. Street modification was found more effective than introducing a 30kph speed limit, and the modification had especially favourable effects for children. On the whole, all groups of road users benefitted from the improvement in traffic safety resulting from the measures. In three other cities, traffic safety was found to be significantly improved in the areas where traffic calming measures were applied. In particular, the number of accidents at intersections was drastically reduced, but there was sometimes a considerable increase in accidents with only minor damage. Weaker road users, including children, pedestrians, and cyclists, benefitted most from the measures.
Samenvatting