Impact of lane width of mountain highway on vehicle lateral position and speed

This study investigated the impact of lane width of mountain highways on driving behaviors (lateral positions and speeds) by using a high-fidelity driving simulator, the Driving Behavior and Traffic Safety (DBTS) simulator. It was developed in two steps. First, the validity of using the driving simulator was tested by comparing results from a field study in a mountain region with those from a driving simulator study. The simulated road was a reconstruction of a real road which was a two-lane mountain highway with a lane width of 3.0m. Then, another three scenarios with the identical driving environment but varying lane widths (2.7m, 3.25m and 3.5m, respectively) were simulated. Given that there are many curve sections on mountain roads, this paper focused on the changes of lateral positions and speeds on curve sections. Results showed that the results were statistically significant, indicating that DBTS simulator could be used as an effective tool for mountain road studies. Moreover, the analysis of vehicle trajectories and speeds showed that lane width and curve radius had considerable impacts on driving behaviors, such as vehicle lateral positions and speeds. The wider the lane was, the larger the lateral position deviations and speeds were. Along with an increase in radii of the curves, lateral position deviations saw a decreasing trend while speeds saw an increasing trend. The influence was more significant for lateral position deviations than for speeds by comparing the variations between different lane width and curves.