Optimization On Vehicle Routing Design Of Flex-route Transit

With the rapid development of China’s economy,the number of motor vehicles has increased,and the proportion of trips of motor vehicle has gradually increased,and traffic jams and pollution have appeared in cities,affecting the quality of people’s life.Public transportation can alleviate traffic congestion and reduce traffic pollution in China.However,in new urban areas with low residents’ travel density,conventional public transit cannot meet diversified needs of travel.In order to solve the above problems and promote the further development of the urban public transport system,flex-route transit came into being.Flex-route transit combines the low cost of fixed-route transit with the flexibility of demand-responsive transit and becomes the key to solve residents’ traveling in new urban areas.The main problem of the operation is design of the route,this paper studies the vehicle routing optimization of flex-route transit.Firstly,the concept,scope of application,and composition of flex-route transit system are briefly introduced.Based on the introduction of two types of vehicle operating rules,normal driving rules and retrograde driving rules,a strategy of vehicle routing design based on retrograde driving rules is proposed and provides a new idea for the design and optimization of vehicle route with flex-route transit.Secondly,the single-vehicle system is taken as the research object,and the routing optimization model of the flex-route transit under the static demand of passengers is set up with the goal of minimizing the weighted sum of vehicle’s running time,passengers’ waiting time and riding time.According to the established selection rule of backtracking point,the route is designed under the retrograde driving rules.By the values of the objective function,the optimal plan of routing design is determined,and the sensitivity analysis of the relevant influencing factors in the retrograde driving rules is performed.Thirdly,in order to fit the actual life and enhance the implementation of the system,comprehensively considering the cost of the enterprise and passengers,and establishing a two-layer planning model for the routing optimization under dynamic demand of passengers.The upper objective is to maximize the number of passengers served by the vehicle and the lower is to minimizing the impact of dynamic passengers served.Based on the results of vehicle routing design under the static demand of passengers,the optimal plan of routing design was finally solved by designing a hybrid solving algorithm combining improved insertion algorithm and "rejecting and reinsertion".Finally,through the analysis of case,the routing optimization model and the algorithm is validated by simulating via MATLAB.This paper takes the operating rules of flex-route transit as the starting point,formulates the selection rule of backtracking point,and proposes a strategy of routing optimization for flex-route transit under the retrograde driving rules,which can further enrich the theory of the flex-route transit system and promote the development of the new system.