The Research On Modeling And Simulation Of Pedestrian-vehicle Mixed Evacuation Based On Cellular Automata

In recent years,the occurrence of large-scale emergencies in the worldwide is more frequent.From the explosion on April 6,2015 about Gulei PX project to the explosion on August 12,2015 in Tianjin,and the terrorist attacks in French on November 13,2015,and so on.These large-scale emergencies put forward higher requirements to large-scale evacuation of the city.Currently,most studies focus on the evacuation process inside the buildings.But the most biggest difference between indoor evacuation and the large-scale evacuation of the whole city lies in that the objects of the large-scale evacuation in the city are not only the pedestrians but also the vehicles.This distinction makes the evacuation situation become more complicated.Thus,the investigation of the urban evacuation with mixed traffic flow in emergency has extremely important theory meaning and practical significance.According to the questions about the pedestrian-vehicle mixed evacuation,we take a road in Xiamen as an example.And based on multiple lanes cellular automata model,we put forward a three-dimensional cellular automaton model of the pedestrian-vehicle mixed evacuation.The model consists of four modules which are initialization module of road network,pedestrian module,vehicle module and data output module.In this paper,we use a single-layer cellular automata model to divide the cell.The road network of pedestrians and vehicles is divided into uniform size cellular.And we also use the three-dimensional cellular automaton model to simulate the pedestrian bridge in the realistic scenes.We use the first floor of three-dimensional cellular network as the surface street,and we use the second floor of three-dimensional cellular network to simulate the pedestrian bridge.About the conflict in the crossroads,we take the traffic regulation by the traffic lights as an example.In this way,we research the influence of the traffic regulation on the efficiency of evacuation in different conditions.we also study the influence of the pedestrian bridge on the efficiency of evacuation in different conditions.Finally,we use the three-dimensional cellular automaton model to study and analyze the evacuation performances with different mixed proportion of pedestrians to vehicles.And we find that there is always an optimal proportion of pedestrians to vehicles.When pedestrian proportion is between 60%and 80%,the mixed evacuation results are better.And the optimal proportion is influenced by the road facilities and traffic regulation.Moreover,we also find that the traffic regulation and the pedestrian bridge can separate the pedestrian flow and vehicle flow,and improve the speed of evacuation and reduce the time of evacuation.Finally,in most situations,traffic regulation can always improve the evacuation efficiency,however,pedestrian bridge has its own limitation.That means if the ratio of pedestrian is more than 80%,the pedestrian evacuation efficiency by the pavement is much better than the efficiency by the pedestrian bridge.