Effects of speed and lane on lateral offset of vehicles in desert expressway

Abstract

Desert expressways feature straight alignments, monotonous roadside environments and limited external disturbances, which lead to distinctive speed selection and lateral control behaviors of drivers. This study aims to explore the coupling mechanism between vehicle speed and lateral trajectory on desert expressways. Taking passenger cars on straight segments of desert expressways as the research objects, this study obtained high-precision vehicle trajectory data through unmanned aerial vehicle field measurement. The speed distribution and lateral offset rules under different speed intervals and lane positions were analyzed. Correlation analysis and regression analysis were adopted to quantify the independent influence of vehicle speed on lateral trajectory characteristics. A multi-dimensional evaluation system was further constructed to determine the optimal safe driving speed ranges for inner and outer lanes.Lane position presents a significant stratified constraint effect on vehicle speed, and obvious heterogeneity exists in trajectory offset features and driving risk levels, between inner and outer lanes. Vehicle speed shows an extremely weak positive correlation with lateral offset, indicating that speed is not the core factor affecting vehicle trajectory behavior on desert expressways.The comprehensive evaluation results demonstrate that the optimal safe speed range for the inner lane is 125–130 km/h, while that for the outer lane is 95–100 km/h. Significant lane-based differences in vehicle lateral trajectory and speed adaptation behavior exist on desert straight expressways. Speed variation has limited influence on trajectory stability, whereas lane location dominate driving safety performance. The defined sectional safe speed intervals can effectively support speed limit calibration, dynamic traffic safety control, and safety facility layout optimization for desert expressways in arid regions.