Route Optimization Of Flex-Route Transit System

Nowadays in China,The contradiction between supply and demand of urban traffic is becoming more and more prominent,so is the problem of traffic congestion.Increasing the sharing rate of public transportation can help to develop low-carbon travel and be instrumental in alleviating the urban traffic pressure,thus contribute to the sustainable development of cities.Encouraging the new mode of flexible transit service,especially the extension and application of flex-route transit service in China,can effectively solve the problem of bus travel in areas with low travel demand density,which is of great significance to the improvement of bus attraction,the alleviation of urban traffic pressure and the development of low-carbon transportation.In this thesis,flex-route transit system is taken as the research object,and the optimization of its vehicle routing problem are analyzed emphatically.The basic concept,operation characteristics are expounded and the corresponding bus system is designed,which can provide the service for more people Through questionnaire survey,the intention of using flex-route transit is analyzed subsequently,the survey results show that there is an urgent need and great potential for flex-route transit service in China,and its application abroad is introduced.also,then the functional positioning and using conditions of flex-route system is thus obtained.By analyzing the difference of the application environment of flex-route system between the domestic and foreign,flex-route system with demand stations which is more suitable for domestic is put-forward.The service area is segmented,the bus demand points are determine by using gravity method,then a site location model based on Voronoi diagram is proposed.Taking the bus company operating costs as well as the passenger waiting time costs and the quantity of demands which the system serviced as the objective functions,The former is to minimize the objective function value,and the latter is to maximize the objective function value.the static and dynamic route optimization model of flex-route transit is established with relaxation time,passengers' boarding and getting off time windows and the departure time windows of fixed sites as constraint conditions.According to the characteristics of these models,the commonly used algorithm is analyzed,a multi-objective genetic simulated annealing algorithm is proposed to solve the models.Through an example,the models are applied to solve the vehicle route with the known reservation demand in the service area,and the algorithm is adopted,which verifies the effectiveness of the flex-route vehicle route optimization model.The operating effect of flex-route transit is compared with that of conventional bus.The experimental results show that the system performance of the flex-route transit is better under a certain travel demand density,which verifies the feasibility of flex-route transi in practical application.