Traffic safety issues have increasingly aroused widespread concern in society, especially traffic accidents caused by severe weather. Due to the existence of the zero cross slope section, the outside lane of the superelevation transition zone of the expressway easily becomes a water accumulation and accidents section on rainy days. Therefore, it is of great significance to study the water accumulation problem of the superelevation transition zone of the expressway on rainy days to enhance the safety of vehicles. Based on the calculation model of water film thickness in HintCAD software, the relationships between water accumulation and highway longitudinal slope, superelevation gradient rate and pavement width were explored, and the corresponding regression models were established. Besides, to reduce the possibility of water accumulation on the road surface at the superelevation transition zone, and to ensure driving safety and operating efficiency, the safety optimization measures for expressway in rainy weather were put forward.

Expressway; Superelevation Transition Zone; Water Accumulation; Roadway Alignment; Optimization Measures