Signal Timing Optimization In Urban Road Network Based On Optimal Exhaust Emissions And System Impedance

With the rapid development of economy and the acceleration of urbanization process,the private car ownership reveals a trend of dramatic increase.The backward transport infrastructure and imperfect management tools bring some consequences that the intersection traffic circulation is becoming more and more urgent,and the traffic efficiency of road network is declining.At the same time,vehicle exhaust emissions in the proportion of environmental pollution gradually increased,which affects people traffic and living environment seriously.How to balance the conflict between economy development and traffic and living environment,which attracts more attentions.Therefore,taking vehicle exhaust emissions and the total system impedance of road network,based on which it is of great practical significance to establish the traffic signal control optimization.Based on the analysis of urban traffic signal control development,the theory is analyzed systematically for urban traffic signal control problem,and the modeling tool and solving algorithm of which is introduced in detail.Then to design the framework of traffic signal optimization system for urban road network,and establish a multi-objective bi-level programming model to minimize the vehicle exhaust emissions and the total impedance of the system.After this,the advanced PSO algorithm is designed to deal with the model based on MATLAB software to verify the superiority of the advanced PSO algorithm.The main research work of this paper is summarized as follows:1.Base on the analysis of urban traffic signal control,vehicle exhaust emissions,bi-level programming model and optimization algorithm,the urban road traffic signal control system is designed by combining traffic signal control with traffic distribution.It consists of input module,signal optimization module,signal evaluation module and output module,a core part of which is the model establishing process and solving algorithm.2.The upper-level model which combined the vehicle emissions and system optimum assignment model is built,and the lower-level model is built based on minimizing the sum of the link travel time function integral.Then to design an adaptive momentary weight coefficient function and mutation operator based on traditional PSO algorithm to avoid the optimizing process prematurely into the local convergence,and use interactive iteration to solve model.3.The topological graph of the real road network is built with VISSIM simulation platform to obtain initial value and simulation results.The optimizing results obtained from MATLAB software are compared and analyzed with initial value and simulation results,and the sensitivity analysis of the optimization results is carried out by adjusting the weighting coefficient of the upper layer problem.