Study On Demand Forecasting And Allocation Of Expressway Emergency Vehicle Resource

ABSTRACT:With the increasing number of expressway traffic accidents, emergency rescue becomes more and more important. Emergency resources are the basis and security in the process of emergency rescue. It has become urgent issues that how to determine the amount of resources required for expressway emergency rescue tasks and allocate resources reasonably so that the expressway accidents can be handled efficiently. Expressway emergency vehicle demand and configuration are studied in this paper. The specific works are as follows:(1) Through summarizing the expressway rescue process, the emergency resource demands of expressway are analyzed and classified. The factors which affect the emergency vehicle resource demands of expressway have been studied by combining with the accident statistics yearbook and accident-causing theory. The accident hazards can be classified into four types such as road conditions, ancillary facilities, weather conditions and traffic volumes. Then two-level index system of expressway accident hazards is established.(2) The structure of cases combining accident hazards and demand results is researched, and then the case-based reasoning model which is suit to quantify the demand of emergency vehicle resources is established. This paper firstly presents that accident hazards and emergency vehicles demand act as key factors in the case base. The AHP method is adopted to calculate the weights of indicators. The innovative amend method that the difference coefficient is proposed to amend the forecasting results due to the difficulty and deficiency of the adjusting of result space in case-based reasoning forecasting.(3) According to the characteristics of the vehicle resources allocation of expressway, the paper analyzes the objective function and constraints. The objective function is determined as that the rescue efficiency will be the highest under the constraint of certain cost. Then the resource allocation model is established by adopting the mathematical programming method with considering the parameters such as the risk degree of road, rescue time, the minimum resource demands, etc. These parameters of model are studied and determined quantitatively.(4) The appropriate particle encoding and the parameters such as learning factor, the maximum and minimum convergence speed and position are studied and determined. What’s more, particle swarm optimization algorithms and resource allocation model are combined to calculate the allocation results. And the process of calculating the configuration model by PSO is established. Finally the program of resource allocation model calculated by POS is developed based MATLAB software platform.(5) The results of the instance application and verification show that the case application shows that case-based reasoning can be better used to predict the emergency vehicle requirements. What’s more, through the difference coefficient revising forecasting results, the accuracy of the results can be improved efficiently and significantly. The particle swarm algorithm can solve the problem of resource allocation global search and have a fast convergence speed. And the results of resource allocation are scientific and reasonable, which can provide good references for practical applications.