Study of Rainfall Impacts on Freeway Traffic Flow Characteristics

摘要

Compared with normal weather, the traffic flow characteristics changed under the condition of adverse weather, which accounted for the difference of driving behavior. The influence of freeway traffic flow characteristics caused by different rainfall intensity was quantified through collecting the Hainan Province Eastern Freeway traffic flow and rainfall data. The speed and density distribution of microscopic parameters about freeway traffic flow under different rains was researched, and the highway two-regime speed density distribution traffic flow model under different rainfall weather conditions was calibrated. Besides, the weather influence coefficient that the rainfall intensity and visibility affect the freeway traffic flow model parameters was determined through regression analysis. The research indicates that it has an greater influence on the maximum highway volume and free flow speed as the rainfall intensity increases. Compared with the normal weather, the maximum flow rate decreases15.7%, 19.1%, 32.5% respectively and the free flow speed decreases 4.4%, 7.3%,10.6% respectively because of light rain, moderate rain and heavy rain weather conditions. In the traffic flow model, the breakpoint density and the speed-intercept of traffic flow model are not obviously relevant with the rainfall intensity.