Research On Multi-objective Variable Speed Limit Control Method Of Urban Expressway

Urban expressway is the main framework of urban road network and an important carrier to connect the traffic inside and outside the city.However,in recent years,the phenomenon of urban expressway congestion often occurs,and traffic travel time significantly increases,resulting in a series of increasingly serious problems such as decreased travel experience,environmental pollution,fuel waste and potential traffic accidents.At the same time,with the increasingly scarce land resources of urban roads,it is not advisable to expand new roads to improve traffic,which leads to the increasing pressure on urban expressway traffic management and control.As an important part of the active control of urban traffic,variable speed limit control has achieved certain results in controlling and improving urban expressway traffic.However,due to the current variable speed limit related research mainly focused on the expressway,there are few studies on urban expressway,and there are problems such as insufficient research precision and single control target.Taking urban expressway as the research object,this paper proposes the solution and decision-making algorithm model of variable speed limit control aiming at improving traffic efficiency,traffic safety,energy saving and emission reduction,and simulates chongqing inner ring road section through the simulation platform to verify the effect of multi-objective variable speed limit control.Combined with simulation experiments in this paper,based on the current expressway speed limit theory to get the driver driving parameters such as velocity,acceleration,number of parking information,analysis the influence of different speed conditions on driver behavior,the influence on traffic and travel time,based on automobile energy distribution and road accident impact curve,analysis of expressway speed of vehicle exhaust emission,fuel consumption and the influence of traffic safety.Secondly,in order to exhaust emissions and fuel consumption,traffic,travel time,and safe driving distance to target variable speed limit optimization model is set up,respectively,to road speed limit parameters,the adjacent sections and expressway speed range as constraint conditions,based on the genetic algorithm model by matching the objective function and fitness function,the constraint conditions to construct multi-objective variable speed-limit control model,based on the MATLAB platform with inner ring fast road in chongqing for example modeling and solving speed limit value and multiple sets of non inferior solution set of the objective function.And then the original evaluation matrix constructed by grey correlation analysis method,the reference sequence,based on the MATLAB platform using vector normalization method,the linear proportional changes in the normalized processing,using the entropy weight method for target assignment,and calculation of correlation coefficient of the variable speed model and correlation,combined with the inner ring in chongqing actual case to solve its variable speed-limit decision solution.Finally,according to the research of actual road conditions are put forward based on the comfort of the variable speed limit layout scheme,based on VISSIM simulation network platform building,calibration parameters,design the experiment conditions,in order to get the simulation evaluation data validation multi-objective optimization variable speed-limit control effect,the results show that the variable speed-limit control to guarantee vehicle safety under the condition of optimization of urban expressway traffic conditions.The research results of this paper can provide a reference for the setting scheme of variable speed limit control on urban expressway,which is of practical significance in alleviating urban expressway congestion,improving traffic efficiency,improving environmental benefits and reducing traffic accident risk.