Urban Bus Lane Network Optimization Based On Travel Time Reliability

With the socio-economic rapid development and urbanization process, urban disease such as traffic congestion and environmental pollution is becoming more and more severe. Urban public transit priority development strategy is proposed to relieve the urban disease. Conventional public transit as the important part of transit should be developed prioritily. As the effective measures of urban public transit priority implement, urban bus lane network optimization has the advantages of less investment, quick results and relative simple realization, etc. So how to optimize and enhance the bus lane network has become necessary to research.This paper recognizes the bus road cell and defines the travel time reliability. From analyzing the travel time reliability forcastting method and the feasibility of applying BP neural network to the travel time reliability estimation, the travel time reliability models based on BP neural network is proposed. At first, based on the analysis of the travel time reliability mechanism, the influence factors are established as the model initial input and output variables.Secondly, urban road sections with or without bus lane travel time reliably forcast models are constructed by Matlab neutral network prediction toolbox.Bus lane setting condition based on the traffic engineering is necessary. After analyzing the connotation of bus lane setting, the coordination, benefit and fair principle are proposed; and the road and traffic conditions corresponding to the three principles of the bus lane setting are established.Based on analysis on the necessity of introducing travel time reliability into bus lane network optimization, bi-level planning model is established based on the travel time reliability. The up level model based on the system benefit is established with maximization of transit network travel time reliability as the objective function and bus lane road and traffic setting conditions and optimization scale as restriction conditions. The low level model based on users benefit is established with minimization of travel cost as the objective function. The solving algorithm of the bi-level planning model is designed in this thesis based on genetic algorithm and stochastic user equilibrium traffic assignment model.This paper takes bus lane network optimization in Chengdu as a case study to analyze and verify the model and its algorithm. A case trial calculation shows that optimal scheme can be got by applying the bus lane network optimization model. So the feasibility of this model is proved.