An-Najah Staff

Analytical evaluation approaches for the safety performance of signalized intersections are  applicable for limited scenarios and conditions; whereas simulation based analysis tools are very flexible and promising. This study is a part of intensive efforts to develop a microscopic simulation model for the safety assessment of signalized intersections. One of the important aspects in analyzing driver maneuver, which has vital impacts on the safety performance of signalized intersections, is vehicle paths. Broadly varying paths may result in widely distributed conflict points with other conflicting movements which may affect the occurrence probability of severe conflicts. Therefore, this paper aims to develop a methodology to reproduce the variations in the paths of turning vehicles (right-turning and left-turning) considering intersection geometry, vehicle type and speed. Several signalized intersections in Nagoya City, Japan with various traffic and geometric characteristics were videotaped. A pre-developed video image processing system TrafficAnalyzer (Suzuki and Nakamura, 2006) is utilized to extract vehicle maneuvers. The analysis revealed that the paths of right-turning vehicles are more sensitive to vehicle speed and turning angle while those of left-turning vehicles are more sensitive to intersection corner radius, turning angle and vehicle speed. For modeling individual vehicle paths, this paper applies the Euler-spiral-based approximation methodology where each trajectory is fitted by an entering Euler spiral curve followed by a circular curve and an exit Euler spiral curve. The proposed
models are unique since they provide a realistic and rational representation of the variations in turning vehicles’ paths inside intersections.