The Study Of Urban Traffic Evacuation And Control Strategy Under The Emergency

Modern city is a region with high vulnerability and concentration of risk.Together with the urban original unreasonable planning, traffic network system isvery vulnerable while urban road network flow is always in a constant state ofoversaturated. Once the incidents outbreak, it is extremely easy to cause large areasof traffic congestion, even paralysis, and it is difficult for people and vehicles to beevacuated in a short time. So it is extremely important to research the urban trafficevacuation and control method under emergency and make travelers transfer largelyto safe areas in the shortest time. It’s also has a practical significance of reducingthe severity of incident consequences and safeguarding people’s safety of the livesand property.First of all, the influence of the emergency on urban traffic and thecharacteristics of urban traffic flow under the emergency are analyzed from thedefinition and classification of the emergency. Judgement standard of emergencytraffic evacuation and control scheme,threshold index of influence scope in thearea of signal control intersection and no signal control intersection are putforward,then the emergency evacuation areas are determined. Traffic requirementanalysis about vehicles of social evacuation and emergency rescue is given, and itis pointed out that the emergency traffic demand is loaded into the evacuationnetwork gradually as time goes on.Then, the road network capacity of evacuation area is analyzed, and roadresistance function of vehicle routing applicable to be studied under the emergencyis chosen. Social evacuation vehicles dynamic path selection model based on thegenetic algorithm is put forward by establishing the dynamic traffic network. It isuseful to make social vehicles avoid congestion sections and get real-time optimalpath accessing to security regions. At the same time, the optimal path model ofemergency rescue vehicles between traffic area refuges and traffic rally point isestablished on the basis of the determination of the emergency shelter capacity andposition. Under the condition of emergency, Evacuation and the enforceableevacuation strategy including intersection, road, regional and people evacuation strategy, and control strategy including single point signal control, signalcoordination control, control system and cooperative control strategy of guidancesystem, are discussed, which provide a reference for traffic managers to developemergency evacuation plans.Finally, the evaluation system of emergency evacuation and control scheme isestablished, index definitions and calculation methods are elaborated so as to guidethe traffic managers to make traffic evacuation scheme scientifically and reasonably,guide the traffic flow to evacuate to safe areas, thus ensuring the efficient and safeoperation of traffic flow in abnormal state of the city.