A Field Study about the Effects of Asymmetric Visual Perception on Lateral Driving Behaviors on Curves

The hypothesis that drivers are balancing perceptual speed on both sides of the visual field is proposed through the analysis of the driver’s decision on lateral positioning. Moreover, the temporal frequency of the occurrence of visual stimuli may have an impact on perceptual speed. This research conducts a series of experiments on right-turn and left-turn freeway curves to investigate the driver’s lateral driving behavior. A series of edge lines are installed on the road surface to act as visual stimuli, with temporal frequency ratios of $1:2$ and $1:4$ on both sides. Three observation sections, namely, the spiral-circle point, midpoint, and circle-spiral point of the curves, are selected to gather the driver’s lateral driving behaviors. The results revealed that drivers deviate from the side with a higher temporal frequency compared with that with a lower temporal frequency on both right-turn and left-turn curves. The average deviation distance with a temporal frequency ratio of $1:4$ is significantly greater than that with a ratio of $1:2$. Additionally, there exists a positive correlation between the deviation distance and the disparity in temporal frequency between both sides. Furthermore, the disparity in temporal frequency and the rate of expansion of the visual angle produce interactive impacts on the lateral position of vehicles. Moreover, the original lateral positions of vehicles affect this interaction. The findings of this study suggest a novel approach to enhance lateral driving maneuvers and provide a constructive countermeasure to prevent accidents on freeway curves.