Study On The Emergency Trafifc Distribution Under The City Crisis

In recent years, city emergencies has occurred frequently caused by naturalfactors, human factors and social factors, and the urban road network has metunprecedented challenges. In order to ensure the safety of lives and property undercity emergencies, the properly maintenance and control of the urban road networkbecome critical. After the outbreak, issues such as the road traffic conditions changeaccordingly, the variations of traffic system characteristics, the fluctuation of trafficflow, the destruction of road facilities and the deficiency of traffic information and soon all impact the decisions of the government or organization, even endanger publicsafety. At the same time, due to the high loss of information, it is difficult to grasp thedisaster information in a short time and provide effective emergency decisions andevacuation-rescue measures.Around the problem how to respond to the traffic mutation reasonably, theresearch of emergency traffic management is firstly carried out both at home andabroad, and the quantitative analysis and research is still in the development stage.The paper study deeply on the problems related to emergency traffic assignment andproposes to model emergency traffic assignment of traffic influence classificationbased on the urban emergencies.Firstly, based on the background of city emergent events, according to thepeculiarity of city emergent events, to evaluate the impact of its traffic, establish thesystem of city emergency traffic impact level. As the affect levels determined, itprovides quantitative analysis basis for urban road traffic impedance function undercity emergencies. Secondly, through the city road impedance function model fittingdifferent levels under the road impedance function, provides the calculation formulafor emergency dynamic traffic assignment, to ensure the effectiveness of road traveltime calculation of city emergency. Finally, combined with the system optimumprinciple, using dynamic traffic assignment model, for the establishment ofemergency traffic assignment model, so as to achieve the rational allocation of Roadcity emergency use right and the ultimate goal of emergency evacuation. Finally, Theemergency traffic impact grade of a city under emergency are examples of judgment,and the dynamic traffic assignment is studied by using simulation software. Thisrevised model is applied to emergency traffic assignment, which has been provedvalid by analyzing the simulation results.