Reliability Analysis of Vehicle Stability on Combined Horizontal and Vertical Alignments: Driving Safety Perspective

Abstract

A driver/vehicle/road closed loop dynamic simulation model considering three-dimensional (3D) alignment was established using Matlab/Simulink for reliability analysis of vehicle stability on the combined horizontal and vertical curve. Pavement friction and vehicle operating speed were considered as the random variables. The point-mass-model based performance function considering the failure model of skidding, vehicle dynamic simulation-based performance function considering the failure model of skidding, and vehicle dynamic simulation-based performance function considering the failure model of rollover were presented, respectively, according to crash types of vehicle occurring on the curve road. Monte Carlo sampling was used to solve reliability. Followed by a parametric study, the results show that the probability of skidding calculated by the vehicle dynamic simulation is larger than that by point-mass model; and the probability of failure decreases with increasing superelevation, while rises with increasing road slope. It indicates that the current horizontal curve design oversimplifies vehicle model, ignores vehicle transient responses, and separates the horizontal and vertical alignments, which could be adverse for vehicles navigating the curved road.