Study On Evacuation Strategy Of Urban Road Traffic Emergency

In recent years, with the rapid development of social economy, the car ownership has increased dramatically while the contradiction between supply and demand of urban road traffic system is increasing. Therefore, traffic jams phenomenon is very common and it is very difficult to organize traffic and control traffic signal more effectively. Various emergencies happened frequently and it always makes seriously influence on urban traffic system. It will cause traffic demand increase and urban transportation network structure change in a short time. Under this situation, it is important to ensure personal safety and evacuation efficiency, meanwhile people who are in traffic incident happened area should be rescued and evacuated immediately. In this paper, based on the definition of urban traffic emergency, the study of urban traffic emergency evacuation strategies is carried out from the aspects of determination of the level of emergency, emergency traffic organization and emergency traffic signal control.Firstly, based on the characteristics of urban road traffic emergency, the level of emergency is determined from the features and effects of the incident using qualitative classification without considering the influence of transportation system characteristic and the rescue ability under the emergency situation. Taking incident and emergency traffic organization factors into consideration, an urban road traffic emergency judgment index system is set up, the index weight is calculated using fuzzy analytic hierarchy process(FAHP) and the emergency incident level evaluation model is established in this paper.Secondly, through the analysis of urban conventional traffic organization mode, combining with the network topology control theory, the road and intersection organization theory under emergency state is studied. Emergency traffic network model is constructed by on-lane modeling, and the corresponding dynamic traffic assignment model is established. The model is solved by macro simulation software TransCAD and the process of an emergency traffic organization plans production is designed.Then, based on the analysis of urban intersection traffic flow characteristics under the emergency situation, and combining the corresponding emergency traffic organization means, the unidirectional green wave traffic control model with no one-way traffic organization for emergency rescue vehicles and the two-direction green wave model with different width are studied respectively according to the principle of green wave traffic control. At the same time, Synchro software is used to design and optimize the green wave traffic control model for the timing.Finally, taking the fire accident near Jiuquan road in Chengguan district of Lanzhou city as an example, the emergency incident level evaluation model, emergency traffic organization and emergency traffic signal control are verified respectively. And the traffic network before and after running characteristics are analyzed comparatively using emergency traffic organization and emergency traffic signal control by microscopic simulation software VISSIM.In this paper, taking urban road traffic emergency as the research object, urban traffic emergency evacuation strategies are studied using the triangular fuzzy number theory, fuzzy analytic hierarchy process(FAHP), the network topology control theory and on-lane network model. The feasibility and the effect of implementation of the emergency evacuation strategies are realized and verified with the help of different traffic simulation software.