Public Transit Assembly Stations Location And Vehicle Routing Plans For Regional Evacuation Under The Typhoon Disaster

Typhoon is the main natural disaster which the southeastern provinces of China often suffer in the summer and autumn seasons and that has brought great loss of property and casualties. So it is very important to prepare the emergency plan before the fall of typhoon for the emergency managers to make right decisions. Considering that China's current economic situation& road transportation development are slower, the urban size& population density are much larger than that in the developed countries and that the popularity of family cars is in the low level, the government has to, if the typhoon occurs, organize the public transportation with large capacity to perform large number and scale of obligatory population evacuation for the purpose of accomplishing the emergency evacuation by efficient use of the city's road network traffic capacity. Under the above situations, this essay analyses how to pick up the evacuation assembly stations and how to plan the evacuating route for the public vehicles under the descent of typhoon, so that the evacuation efficiency can be improved and the casualties& loss of property can also be reduced to the lowest level.In order to depict the real evacuation situation when the typhoon occurs, the essay comes up with the definition of coverage percent of the evacuation response time and the technique of network modeling for the time-space expansion, which based on the systematic analysis of the characteristics of the typhoon and those of the evacuation management& demand of public transportation. The essay is trying to analyze the correlation between the station selection of public transportation assembly and the decision of route planning of evacuating vehicles and also build model of the bi-level planning of station selection and passing route.As stated on the blow, the bi-level planning of stations selection& route not only guarantees the quickness of evacuating vehicles but also ensures the globality of evacuated personnel as a result that it provides the important model support for the efficient evacuation plan. In the upper level of decision, it focuses on considering establishing the optimal evacuation route for the evacuating public vehicles so that the victims are able to arrive in the safe area as soon as possible. Given the position of several evacuation assembly stations and the personnel arrangement of the evacuation community, the upper model is trying to solve the vehicle routing problem (shorted from VRP), whose objective function is the shortest time spent on evacuation (including the waiting time spent). In the lower level, it focuses on considering how to choose the optimal position of assembly stations and the personnel arrangement in order to evacuate as many victims as possible. Given the demand of the evacuation community& the alternative assembly stations, the objective function is the total coverage percent of demand met by the utmost efforts, and the question is to solve the Maximum Covering Location Problems (shorted from MCLP). Considering complexity of the bi-level programming model, there are many restrictions and it is non deterministic polynomial (shorted from NP-hard). In the situation we find the solution for model by genetic algorithm. Through the chromosome coding strategy, the best planning strategy are figured out quickly after selection, crossover and mutation process..