Research On The Design Of Speed Limit For Environmentally Friendly Urban Links Based On Simulation Optimization

In recent years,urban smog has intensified,and air pollution has seriously hampered the development of cities and has become an urgent problem for urban managers.Traffic pollution is undoubtedly a major cause of urban air pollution.Not only that,the problem of urban traffic congestion has been plaguing us for many years.This paper attempts to find a reasonable urban link speed limit design method based on environmental factors,and uses an analytical method to construct an environmentally friendly urban link speed limit design model and calculate it.The simulation method is used to calculate the most environmentally friendly traffic network speed limit.Finally,the method of simulation optimization is used to solve the design problem of urban link speed limit considering environmental protection factors,so as to improve traffic efficiency and reduce traffic environment pollution under the existing traffic network conditions.Firstly,this paper analyzes the traditional traffic assignment model and adds the condition of urban link speed limit based on this,and observes the change of user equilibrium model after adding urban link speed limit.Considering that the traditional user equilibrium model only pays attention to the travel time factor,this paper constructs the traveler’s negative utility function,which includes the traveler’s travel time,driving safety,speeding penalty and fuel consumption rate.The traveler’s negative utility function replaces the travel time function in the traditional user equilibrium model.Because the traffic manager’s goal is that the overall pollution discharge of the traffic network is the smallest,which is inconsistent with the traveler’s goal,this paper constructs an environmentally friendly urban link speed limit design model using the two-layer planning model.The upper model aims to reduce the total pollution of the network,this represents the goal of the traffic manager.The lower model is a modified user equilibrium model that represents the target of the traveler.After that,this paper uses the small case to carry out the model calculation and proves the feasibility of this model.Then,considering the deficiencies of the analytical model in terms of accuracy,this paper builds a simulation platform based on Paramics and MOVES to calculate the environmentally friendly urban link speed limit design of the link.Paramics is a micro-city traffic simulation software.Through Paramics we can simulate the network to be solved and get the virtual running status of the traffic network.Then,according to the operation status of the traffic network obtained by Paramics,the MOVES traffic pollution discharge software accurately calculates the total pollution discharge of the traffic network,thereby obtaining more accurate calculation results.Subsequently,due to the low computational efficiency of the simulation platform,the simulation optimization process is carried out in this paper.The meta-model method is used to combine the analytical model with the simulation platform,and the constructed meta-model is calculated by using the confidence domain non-derivative model in the multi-model algorithm.This method can make the calculation of the environmentally friendly urban link speed limit design a balance between accuracy and computational efficiency,thus achieving the purpose of simulation optimization.Finally,this paper takes Beijing Second Ring Road Network as an example to verify the above simulation optimization method.The results show that the simulation optimization method can improve the calculation efficiency of the model to a certain extent while ensuring the accuracy of the calculation results.