ACCIDENT RATES AND HOURLY TRAFFIC FLOWS ON URBAN ROADS

The connection between traffic volumes and accident rates on sections of inner urban roads has been investigated. In order to exclude from further analysis the extremely high accident rates in the limiting region of traffic flows, which are based only on low absolute accident numbers, a normal range of traffic flows was defined. Within this normal range equalizing lines between accident rates and traffic flow were calculated, which enabled the comparison of this relationship for the 19 lengths of road investigated. The rate of increase of the equalizing lines differs greatly from street to street. The Hamburg results do not completely exclude the possibility that within the defined normal range a tendential decline of the accident rate in line with traffic flow could be present. The Munich results do not allow a similar statement to be made, amongst other reasons, because of the low range of observed traffic flow values. (TRRL)