With the "Merkblatt zur Verbesserung der Verkehrssicherheit auf Motorradstrecken" (MVMot (FGSV, 2007)) exists an aid to determine accident black spots for powered two wheelers on rural roads. Until now, urban areas are not covered although about 2/3 of accidents involving powered two-wheelers with personal injuries take place in urban areas (DESTATIS, 2012). By using multivariate statistical methods, problems in accident analysis, such as the estimation of the influence of traffic volume or other influences on the accident frequency can be described. Appropriate measurements are derived from typical findings in accident constellations and deficits. In addition to deriving thresholds based on an absolute number of accidents, a further approach is being made by using the share of accidents powered two-wheelers contribute in common accident black spots. The theoretical considerations for the development of threshold values are based on an optimization of the cost benefit ratio. Costs are understood as the amount of blackspots that need to be handled whereas the benefits lie in the amount of accidents that can be prevented by installing appropriate measurements. Within the determined accident black spots for powered two-wheelers typical accident constellations are identified. The analysis of accident reports and the involved locations allow the determination of special deficits of an accident constellation. The result is a catalogue of measurements for typical constellations of accidents involving powered two-wheelers. Using generalized linear models allows the quantification of the systematic effects continuous or categorical variables have on the accident frequency. Models for links and intersections of the main road network have been developed which differ in their right of way and the type of intersection (crossroads and junctions). For unknown traffic volumes no models could be developed for the elements. Models for intersections with known traffic volume can describe 60 70% of the systematic variance of the accident frequency. Most of the variance can be explained by the influence of traffic volume (or traffic volume split up on major/ minor driveways). Other systematic influence on the accident frequency can be described by the existence of tramway tracks, increased pedestrian crossings on commercial streets (business, service, shops in the environment as a proxy variable) and the condition of the road surface (number of bus/ tram stops in the environment as a proxy variable for ruts)A sufficient description of the accident frequency on segments requires the implementation of varying lengths. The investigation of the blackspots showed recurring deficits: - driving up tramway tracks in a low angle, - lack of vision, - ruts, - roundabouts at city limits, - bad recognizable right of way regulation, - change of grip (bitumen, large ground markings), - high speeds, - sudden brake maneuvers. For recurring accident constellations the catalogue of measurements can hint on typical deficits and local conditions affecting the safety of powered two-wheelers. (Author/publisher)
Abstract