The effects of geometric characteristics on the accidents of the A3 Naples-Salerno, which is among the riskiest motorway in Campania (Italy), are reported in this paper. For the purpose, all the accidents which occurred during a twenty month period (August 1998 - March 2000) from Km 5+00 Km 55+00 (for a section of 50.0 km) have been examined. All the information on the accidents were taken from the Road Police reports, while the horizontal and vertical alignments were obtained from the road plan. The study was carried out by the univariate analysis therefore the accident data were related to the following single variables: length of tangents, radii of circular curves(R), longitudinal grade(plus or minus i), change in operating speeds between two consecutive geometric elements having constant curvature and sight distance. Therefore relationships between these geometric parameters and the accidents which occurred on the motorway studied, that is a four-lanes median-separated road, have been developed. The accident data have also been related to the pavement surface conditions, so relationships to the Side Friction Coefficient (CAT) and macro-texture (HS) have been developed too. (A) For the covering abstract of the conference see ITRD no 207828. The reprints are also available at the web - http://www.vti.se/pdf/reports/K18APart1.pdf; http://www.vti.se/pdf/reports/K18APart2.pdf and http://www.vti.se/pdf/reports/K18APart3.pdf.
Abstract