Research On Service Area Design For Flexible Transit System

With rapid development of urbanization and motorization in China,the transportation problem is growing even worse.Public transportation is superior on high capacity,low cost,high efficiency and low pollution.In this context,priority development of public transportation becomes an efficient method to solve such problems.However,there still a mismatch between urban develop and public transportation develop,some regions have lower sharing rate of public transportation,the supply and demand imbalance is still exist.Flexible Transit System(FTS)is a new traffic mode that apply to low travel density area,it has both the advantages of Fix-Route Transit(FRT)and Demand Response Transit(DRT),FTS could satisfy people's individual travel demand.By far,the research on FTS is still in early stage in China,the study on planning and designing of FTS has important theoretical and practical value.This paper focus on the design of service area of FTS,provide theoretical basis for the extension and application of FTS in China.Firstly,the concepts of FTS is described and the operating conditions,principles,rules are summarized,based on such concepts and the conditions in China,the construct steps of service area of FTS are proposed,the follow-up study is developed based on such steps.Secondly,according to the relationship between slack time of system and vehicle travel time,the calculation formula of system initial service area width is obtained.Meanwhile,sensitivity analysis of related parameters are carried out to explore their change regulation.Thirdly,based on the confirmed service area width,drawing lessons from traffic planning,the initial rectangle service area is divided into several service quarters,in order to screen such service quarters,confirm final service scope,there is a service stop set in each service quarter,and a service area selection model is built.And considering the characteristics of this model,corresponding greedy algorithm is designed to solve such model.Finally,a data experimental is designed to test and verify the effectiveness of service area selection model.Lowest slack time utilization ratio and weight of walking time are analyzed to research the influences on final result by such two parameters.