An integrated model study on the analysis of the influence of heavy rainfall on traffic congestion

Traffic congestion induced by urban water-logging in heavy rain is a typical case of disaster chain. To optimize traffic with weather-related timing traffic lights, traffic conditions under adverse weather needs to be predicted. In this paper, an integrated model for predicting the influence of heavy rainfall on traffic congestion is developed considering that rainfall affects traffic conditions by impacting drivers´ behavior with water-logging on the road. The model consists of three parts. Firstly, the distribution of water-logging on driveway was calculated with SWMM. Secondly, individual driver´s behavior to different depth of water was analyzed with the use of fuzzy logic method. And finally a cellular automata model for traffic simulation was built to study the whole traffic conditions in rainfall with the results of previous two parts as input. To illustrate the integrated model, 5 cases for single lane were simulated. It is shown that traffic congestion seems to be more serious in concave areas and the interaction among cars may aggravate the impact of rainfall on traffic flow.