Simulation on Vehicle Driving Characteristics and Safety of T Interchange

Interchanges affect traffic efficiency of expressways and are also the sections with high accident rate. The aim of this study is to investigate driving characteristics and safety of a typical T interchange. A driver-road-vehicle model was developed. Speed control was defined using path preview, which quite differed from the constant speed model. Driving simulations were carried out under different upper speed limits (USL) and road friction coefficients. Results show while driving at a relatively high USL, the vehicle decelerated before entering the circular curve with the minimum radius and accelerated after negotiating this curve. With increases in the USL the deceleration process advanced, while the starting stations of the acceleration were accordant regardless of the USL. Vehicle lateral acceleration characteristics were analyzed, according to which the risky station and section were found for the ramps. Finally, several measures were proposed to enhance driving safety for the T interchange.