The second internal report includes the preliminary results of the SPF development. Based on a huge accident data base of a 500 km part of the Saxony road network various approaches has been developed in order to find the most appropriate correlations results. Since the SPF will base mainly on geometric input values three different road section types has been worked out which consider the alignment properties in different ways. Road section type one bases on the node structure, type two defines sections based on a pre-analysis of the accident occurrence and type three bases on an evaluation of the existing horizontal alignment. All types are attributed to the alignment by using the geometric parameters curvature change rate, curve radius, and road width. The analysis of the accident occurrence includes the calculation of accident rates and accident cost rates. Two different accident scenarios were tested: scenario one includes all accident types; scenario two includes driving accidents and accidents in longitudinal direction only, because these two accident types are mainly connected with the geometric alignment. For each section type correlation models were calculated and compared. The results show good correlation between geometric and accident parameters. Also it was worked out that the accident scenarios mainly influence the results. The combination of section type 'alignment classification' and accident scenario two are characterised by the best correlation results. (Author/publisher)
Abstract