A study on the optimal safety speed and warning sign distance for highways in windy and sandy environments based on driving behavior

This study aims to address the issue of driving safety on highways in the desert region of Northwest China during extreme weather conditions such as sandstorms, with the goal of reducing driver risk. It explores driver behavior under extreme conditions of sandstorms and sand accumulation, proposing safety speed recommendations and warning models for different environments to calculate the optimal warning distance in windy and sandy conditions. Natural driving simulation experiments were conducted in windy and sandy environments, collecting driving behavior data from 45 drivers under varying visibility and road conditions with or without sand accumulation. This data were utilized to determine safe speeds before and after deceleration, as well as before and after lane changes. Warning models were established for both sandstorm and sand accumulation conditions. Driving stages in sandy environments were classified into normal driving, deceleration and low-speed stable driving phases. In sandstorm-sand accumulation environments, the stages included driving, lane changing and low-speed stable driving after lane changes. The recommended post-deceleration speeds for visibility levels of 2000, 500, 300, 150, 100 and 50 m were 120 km/h, 90 km/h, 70 km/h, 60 km/h, 50 km/h and 40 km/h, respectively. The recommended speeds after lane changes in sand-accumulated areas were 90 km/h, 80 km/h, 60 km/h, 60 km/h, 50 km/h and 40 km/h. The optimal warning distance for highways in windy and sandy environments was calculated to be 1100 m. The recommended safe speeds under different visibility conditions in sandstorms and sand accumulation environments are important references for future regulations. The suggested warning distance for highway signs is 1100 m, which can effectively ensure driving safety and reduce accident risks.