Research On Network Partition And Carrying Capacity For Regional Gating Control

As an emerging regional control method,regional gating control provides a new idea for mitigating regional traffic congestion.Network partition and carrying capacity estimation are important support for regional gating control.The existing network partition for gating control has problems such as insufficient coordination of internal intersections in subzones,and does not organically combine purpose of various control subzones.Based on the vehicle travel trajectory data,this study uses the method of community division and spectral clustering as the means to study the preliminary control sub-area based on the correlation of the vehicle's travel trajectory at the intersection,and the gating control sub-area based on the vehicle density distribution of the road segment,and the carrying capacity of gating control subzone is studied.The specific research content is as follows.The preliminary control sub-area division method based on the vehicle travel trajectory information and community division algorithm preliminarily divides the road network,so that the travel trajectory or the area where the travel demand is concentrated forms a relatively independent preliminary control sub-area to enhance the intersection in the sub-area.The preliminary control subzone division method provides a preliminary division scheme for the subsequent division of the gating control subzone.The method firstly analyzes the correlation between all pairs of intersections on the road network based on the vehicle travel trajectory,and constructs a non-directional weighted graph of the all-connectivity with the intersection as the vertex.The correlation edge is selected repeatedly and the Newman fast algorithm is used to divide the subzone.The scheme with the best subzone connectivity is selected as the optimal preliminary control subzone partitioning scheme under different undirected weighted graph correlation edge screening ratios.On the basis of the preliminary control sub-area division scheme,the preliminary control sub-area is further finely divided into multiple gating control sub-areas,so that the density of vehicles in the internal sections of each sub-area is similar,and the mean value of vehicle density in sub-section sections is relatively large,so that later Accurately carry out regional carrying capacity estimation,and provide more reliable regional road network critical state information for threshold control.This method first uses the vehicle travel trajectory data to estimate the vehicle density of each road segment,and then calculates the similarity between the road segments based on the "local scale" idea and constructs a similarity matrix.On this basis,the multi-way spectral clustering algorithm is used to divide the road network into multiple initial subzones and subzone iteratively merge to determine the better partitioning scheme.Finally,the best partitioning scheme under different initial subzones is used as the final regional gating control subzone partitioning scheme.By comparing the method with the twoway spectral clustering iterative partitioning-merging method,the results show that the proposed method has better universality and partitioning effect,which provides a better regional partitioning scheme for subsequent regional carrying capacity estimation.The regional road network carrying capacity reflects the maximum cumulative number of vehicles that the road network can withstand under stable traffic conditions,and is an important support for urban traffic control.The traditional method of calculating the carrying capacity has the defects of complex structure,difficult data acquisition,and difficult to verify theoretical assumptions.Based on the emerging MFD theory in recent years,this paper analyzes the carrying capacity of the gating control subzone,which has the outstanding advantages of easy data acquisition,simple model relationship and high practicability.Based on the regional gating control subzone division scheme,this part first constructs the MFD of the gating control subzone based on the vehicle travel trajectory data,and analyzes the MFD of the subzone at each time of day,the morning and evening peaks of each day of the week.In order to establish a quantitative relationship between the variables of MFD,this part denoises the MFD scatter based on the H-S principal curve algorithm,and then fits the centroid of the main curve by comparing various fitting functions to determine that the rational function is more in line with the change trend of MFD.Based on this,the peak carrying capacity of the subzone workday and weekend morning and evening was estimated.