Driving Simulation Study of Traffic Flow Characteristics of the Climbing Lane on a Two-Lane Rural Road

The climbing lane is a benefit to traffic safety through changing the traffic flow characteristics of the highway and avoiding overtaking maneuvers. This study was conducted by means of a driving simulator experiment to examine the effects of a climbing lane on an upgrade of an existing two-lane rural highway in Yunnan province. To construct and improve the fidelity of traffic flow scenarios on the driving simulator, simulated traffic flows under two special traffic volumes with and without the climbing lane were obtained from VISSIM. Thirty-two subjects were selected to drive on the test road in the driving simulator. On the basis of the simulation results, comparison evaluations of speed and track lateral position of the test vehicle along the section with and without climbing lane were conducted. In addition some simulation experiments from VISSIM were done to find the threshold of traffic volume for the setting of climbing lane. The result shows that there is a higher and steady speed after setting a climbing lane under different given traffic volumes. Moreover, it reduces conflicts with cars from the opposite direction. But this benefit will be reversed with the increase of traffic volumes.