Study On The Dynamic Stop Selection And Timetable Creation For Flex-route Transit

With the sustained and rapid development of social economy,urban sprawl and residents' travel demand characteristics bring new challenges to urban transport in China.The popularity of private cars and the increased car ownership result in serious traffic congestion and traffic pollution in metropolitan areas.In this context,public transport is considered to be the main means of solving urban traffic problems with its features of intension,high efficiency,energy saving and environmental protection.However,urban sprawl and population dispersion lead to the problem that conventional fixed-route transit cannot economically and adequately respond to existing individual requests owing to its low quanlity of service obviously.Being broadly recognized as a new type of public transport service,flexible transit service which combines fixed-route transit and pure demand responsive transit features can solve the last kilometers problem efficiently and should be vigorously implemented.Meanwhile,massive data and advanced communication technologies also provide it with technical support in the Internet era.Therefore,we intend to study flex-route transit system in this paper,and focus on pre-defined and dynamic stop selection and timetable creation.Firstly,the related concepts,such as service area and slack time,are expounded.Based on the introduction of two operation modes of fixed-route transit and common flex-route transit,another flex-route transit mode including pre-defined and dynamic stops is proposed,which lays the foundation for the local design of flex-route transit.Secondly,on the basis of studying the calculation method of slack time,a model related to dynamic stop selection is established for a single-vehicle flex-route transit service system.The objective is constructed to minimize the weighted sum of the expected walking time,the expected waiting time,and the expected riding time.Numerical studies which include model solving,applicability and sensitivity analysis are performed via MATLAB.Thirdly,based on the stop and route design results obtained from the stop selection model,the timetable creatation model considering time window of departure is established,which refers to a multi-vehicle flex-route transit service system.On the consideration of passenger cost and operating cost,the model is aimed to determine the optimal departure interval,frequency and the number of vehicles,then create timetable for flex-route transit.Finally,datas with respect to stop information,passenger flow information,vehicle configuration and vehicle operating information of a conventional urban-rural transit in Xi'an are selected to verify the feasibility of the models.The results show that the flex-route transit mode including pre-defined and dynamic stops has more advantages in China.Combined with development of transit syetem,the study is conducted to stimulate the development of flex-route transit service systems,improve the urban transit system in China,and promotes the sustainable development of urban transport.