Study on Traffic Control Effectiveness and Road Network Stability Based on Macroscopic Fundamental Diagram
The network traffic flow output level and maintenance capability of regional urban road network are different with different control schemes.To evaluate regional traffic control system,it is necessary to analyze the characteristic value of coupling of traffic flow and road network under regional control.As a basic attribute of road network,the macroscopic fundamental diagram(MFD)is selected as a reliable carrier for evaluating the regional traffic control.Compared with the single point evaluation of road sections and intersections,the advantages are analyzed.The evaluation of regional traffic control based on MFD is not affected by the change of traffic demand.There are 5 indicators established,including maximum network weighted flow,accumulative vehicle number,capacity of road network,equilibrium of traffic flow distribution,and time series equilibrium are introduced to evaluate the control effectiveness and road network stability of regional traffic signal control schemes.The effectiveness of regional traffic signal control schemes and the stability of road network operation are evaluated.The traffic flow maintenance ability of road network during peak hours is interpreted.Taking 37 signalized intersections near a road in Chengdu as a road network,and using the reengineering technology of VISSIM,the network MFDs with 4 control schemes are obtained,which are timing control,induction control,adaptive control,and adaptive coordination control.By comparing the morphological characteristics and evaluation indicators of each control scheme,the characteristics and applicability of each control scheme are compared from multiple dimensions.The corresponding control effectiveness is analyzed,the maintenance capability of traffic flow from flat peak to supersaturation is analyzed,and then the operation efficiency of road network with specific control scheme can be understood.Simultaneously,according to the stability performance of corresponding control methods,the limitations are point out.That is helpful to analyze the traffic control strategies in practical application.
ITScontrol effectivenessmacroscopic fundamental diagramroad network stabilitytraffic flow equilibrium
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