Keywords: freeway traffic, motorway traffic, rainfall impact, non–parametric testing, traffic volume, travel time, China, precipitation intensity, passenger cars
Study of the impact of rainfall on freeway traffic flow in Southeast China
The purpose of this paper is to quantify the impact of rainfall on freeway traffic flow using toll station data and precipitation data. Five rainfall categories were classified based on precipitation intensity. Hourly traffic volume and travel times were retrieved and analysed in three spatial scales: at toll stations, on freeway sections between two toll stations, and on freeway corridors composed of multiple sections. Travel times for passenger cars in each rainfall category were studied and the impact of rainfall on traffic volume and travel time was quantified. The non–parametric Kruskal–Wallis test was performed to check the significance of difference among various categories.Calculated traffic volume reduction coefficients and travel time incremental coefficients for each rainfall category were compared with existing research results, which showed obvious differences. Potential causes are discussed to explain the discrepancy in coefficient values.