A NEW METHODOLOGY OF ACCIDENT ANALYSIS USING SAFETY INDICATORS RELATED TO FUNCTIONAL ROAD CLASSES

In Italy the recommended methodology of road classification (not in force yet) has been elaborated as a procedure in which it is required to evaluate several aspects: the role of the road in the territory and in the road network, the environmental context, the typology of traffic, air and noise pollution and road safety. To integrate the methodology of road classification with accident analysis, some safety indicators have been defined. By the use of them, a new methodology of safety analysis has been elaborated by the University of Brescia. For each road segment the accident rate is determined; it is calculated as a function of the total number of road accidents, the extension in km of the considered road segment and the average daily traffic along that segment. This indicator puts in relation the number of road accidents that have happened in the last 5 years with traffic. In relation to the road functional classification, it is possible to calculate the average value of the accident rate corresponding to all the road segments classified in the same road class. From this calculation a control value for each road functional class is obtained. This methodology can be useful to: evaluate the safety level of a road segment in relation to the control value of the corresponding road functional class; determine the road segments where infrastructural interventions are needed, giving priority to those segments where the values of the accident rate are greater; compare the obtained accident rates between different regions and countries in relation to the corresponding functional road classes; and define, at a regional level, an accident goal rate for each road functional class.