Research On Reliability Evaluation Of Multi-Scale Normal Bus Transit Network

With the implementation of the “public transport priority” strategy in China,the normal bus transit service system in major cities has gradually achieved scale,greatly improving residents’ travel experience.However,in recent years,the frequent occurrence of urban traffic congestion and the obvious impact on the operation of bus network have led to the decline of the reliability of the operation of the normal bus system(such as inaccuracy,long waiting time in the bus station,etc.),resulting in a declining trend of the urban bus sharing rate.As the basis of the following network adjustment and operation scheduling strategy optimization,bus reliability evaluation has important practical significance for improving the attractiveness of normal buses.However,the traditional reliability analysis methods based on the bus network topology structure only consider the topology characteristics of the bus network from the macro level,and are less related to the actual bus operation characteristics.The application scenarios are limited,and the development of advanced data acquisition technology brings a large number of bus data resources for analysis.Therefore,how to make full use of the data,around the bus passenger transport access operation mission is guarantee,combining the feature of the bus transit network operation and service,from different scales to explore suitable for reliability assessment theory of normal bus transit network in our country,to improve the quality of bus service,lower operating costs and improve bus attraction has important theoretical and practical application value.This work was supported by the National Key Research and Development Program of China(2017YFC0840206).Based on the above background,this research focuses on the reliability evaluation theory of operation of the bus transit system with fully combining the operation characteristics and the previous theoretical research.Based on the bus transit big data,and taking the consideration of relevant elements of normal bus transit network systems,such as bus transit network,bus transit corridors,transit routes,links or sections of inter station and bus stations,this paper develops a methodological framework of reliability evaluation method of normal bus transit network for macro-,meso-and micro-levels network,and verifies the effectiveness and applicability of the proposed model and method through simulation and empirical analysis.This research is organized as follows.(1)The macro reliability evaluation method of normal bus transit network is proposed.Firstly,the basic concept of normal bus transit network is discussed,and the indicators and shortcomings of traditional network topology are analyzed.Secondly,based on graph theory,the construction method of directed normal bus network topology is proposed.Thirdly,based on the system reliability theory,the definition of static reliability of normal bus network topology is defined,and the static index of network topology based on graph theory is selected.Finally,based on the basic data of bus transit networks such as Beijing,Tianjin and Chongqing,this paper establishes the normal bus transit directed network,verifies and analyzes the proposed evaluation method,and puts forward suggestions on the use of topological indicators combined with the evaluation of local public transport cities and local bus transit network tracking evaluation in the future,so as to provide theoretical support for the planning and evaluation of bus transit network.(2)A reliability evaluation method of normal bus transit network considering passenger flow is proposed.Firstly,based on graph theory,the point passenger flow and side section passenger flow are introduced as weights to establish the capacity network of public transport network.Secondly,it puts forward the definition of multi-dimensional measurement indicators in the case of “attack” of bus transit network,and analyzes the interaction between passenger flow factors and reliability in the line.Thirdly,four “attack strategy” scenarios are proposed for the bus line network.Based on the failure reliability theory,the reliability evaluation method and evaluation measure of the bus line network considering the passenger flow factor are proposed.Finally,through the verification of the actual bus line data,we get the reliability analysis results when the bus line network is “attacked by the whole line”,and put forward suggestions according to the situation,so as to provide decision support for the diagnosis,optimization and adjustment of the bus line network.(3)A meso reliability evaluation method of normal bus corridor network based on“three states” is proposed.Firstly,the bus transit network is abstracted into a network system composed of bus lines,inter station paths and other basic units,and the models of“series parallel system” and “parallel series system” of bus transit corridor network are established.Secondly,it is proposed to consider the three states of “normal operation”,“open circuit failure” and “short circuit failure” to evaluate the reliability of the bus corridor network system.Finally,take the bus corridor under certain conditions as the scene for simulation verification,and draw the conclusions of bus corridor reliability evaluation and optimal configuration of lines and stations under three states.The study combines reliability with line network design factors to provide reference for bus corridor network optimization,bus corridor design and bus line organization and scheduling.(4)A micro reliability evaluation method of normal bus lines based on Copula theory is proposed.Firstly,it discusses the relevant theory of Copula function and the reason why it is selected to describe the relationship between the line and the path between stations.Secondly,taking a single bus line as the research object,the reliability evaluation indexes are constructed,including the average operation time,punctuality rate and average operation time between stations of the whole line,as well as the average operation speed,standard deviation and coefficient of variation of the routes between bus stations.Thirdly,the evaluation model of bus line operation reliability based on Copula theory is established,and the selection of Copula function and the parameter estimation method in the model are discussed.Finally,the evaluation method is verified by using the actual data,and the relationship between the overall reliability of the line and the reliability of inter station path is analyzed,which provides a reference for the diagnosis and evaluation of bus line operation and the optimization of operation service.In this paper,the research results are universal and practical,and can provide theoretical support for the reliability evaluation of normal bus transit network.The research results of multiple scales will provide technical support for bus transit network optimization,bus transit corridor line organization and scheduling,bus transit line operation management service and guarantee,and have theoretical and practical significance for promoting the sustainable development of normal bus transit system.