Excessive or insufficient driving load disrupts driving comfort and highway coordination, increasing accident risk. This study examines the relationship between highway alignment and driving comfort, analyzing its effects on drivers' physiological responses and driving load. A naturalistic driving experiment collected eye movement and heart rate data from 28 drivers. Heart rate increase rate and pupil area change rate were selected as driving load indicators, and an entropy weight method was applied to establish a model. Using k-means clustering, driving load thresholds (0.34, 0.64) were determined, classifying comfort levels as “comfortable,” “moderately comfortable,” and “uncomfortable.” Results show that steep slopes, small curve radii, and complex curved-slope sections increase driving load and reduce comfort. Alignment indices exhibit a “threshold effect,” where exceeding comfort limits intensifies stress responses and lowers comfort. This study provides theoretical support for mountainous highway reconstruction and management.
Meng et al. (Wed,) studied this question.