Computation-based Dynamic Driving Simulation for Evaluation of Mountain Roads with Complex Shapes: A Case Study

AbstractLower standard rural roads with a design speed less than 40km/h account for more than 80% of total roadway network in China. In most situations, vehicles on these rural roads are of free traffic flow, and the driving stability of a vehicle is therefore mostly influenced by alignments and road surface. Single-vehicle run-off-road crashes are often associated with poor road conditions. Therefore, the improvement of alignment design of the roads can be effective to reduce the number of traffic accidents. This research targets at the analysis of driving in several sections of a four-class rural road in Yunan province, China, with varying alignments and complex shapes. In this context, a road creation module, a vehicle dynamics model, and driver module are established in computing environment, and integrated into a “roadway-driver-vehicle” virtual driving system. Driving simulations of a passenger car model on the test segments are conducted. Speed, driver workload, and ride comfort are analyzed in relation to varying geometric alignments. The simulation results show that: by balancing the design parameters of adjacent curve radii and the tangent length in-between, critical safety driving speed on lower standard rural roads can be obtained; the use of hairpin curves and the absence of spirals would lead to a rapid increase in both angular speed of steering wheel and lateral acceleration change rate, resulting in increasing driver nervousness and passenger discomfort