Key Technology Research On Traffic Signal Coordination Control Of Freeway Segment

Urban freeway is a kind of rapid transit corridor with large volume traffic. In order toensure urban freeway’s fast and smooth feature, traffic management department usually takeslimiting control measures in ramp metering to suppress excessive fast road traffic demand.To some extent, although such methods may improve the operating efficiency of the fastroad, congestion will be transferred to link roads related to congested city roads and fast roads.Vehicles queuing at the entrance ramp extending to city road, it will seriously affect thenormal passage of ground road traffic, on the basis of ramp control study, three key problemareas for roads coordinated control study, and then thinking based on hierarchicaloptimization establish expressway ramp and multi-intersections group control barebonesoptimal collaborative optimization model, and simulation and verification examples. Themain research work done with the research results are summarized as follows:First, a detailed analysis of the current situation of the basic research of urbanexpressway ramp control and on top of the existing ramp research methods to study theproblem of cooperative control needs fast road pavement and roads intersection group,concise Freeway and roads intersection control group synergy key issues and proposedexpressway ramp and roads intersection group cooperative control concept.Secondly, Freeway segment type, type and ramp metering control effect were analyzed tostudy the entrance ramp of the main priority control, ramp and ramp signal alternating trafficcontrol strategy is proposed based on support vector machine ramp control improvedalgorithm, and through a case study of Guangzhou City proved the improved algorithm canmeet the changing urban expressway road traffic control needs.Then, the key issues for the coordination and control of arterial roads have been studied.In terms of sub-division of district, a model of sub-district division has been established andthe quick process of division of the sub-region has been determined and dynamic partitioningmethod about coordinated control sub-region has been proposed. In terms of consideringdynamic red dissipate time queuing model, the method taking the dynamic red phasedifference calculation dissipate time into account has been proposed and the MAXBANDmodel has been improved. In terms of phase sequence optimization, a left turn off the lagphase sequence early on bandwidth effects model has been established. Finally, an example isused to verify the feasibility of the appropriate solutions to three key issues.Next, the idea of hierarchical optimization is introduced into cooperative control,establishing an optimal control model with regard to freeway ramp and intersection group. The order parameter equation and the orderly function are used to optimize and determine theweighting coefficients of performance parameters about expressway ramp control andintersection group control, considering the synergies between the expressway ramp controland intersection group control and the degree of the road network congestion caused byslaving effect of different traffic flow. In the process of solving the model, using two adjacentcontrol cycle as a big cycle, the calculation method of optimizing iterations under great cyclecontrol has been proposed to ensure the continuity and consequence.Finally, a loop section of the road in Guangzhou has been selected as the research object.Based on the actual investigation and analysis of the research objectives, the cooperativecontrol simulation model concerning expressway ramp and road intersections group has beenbuilt. Each parameter in the microscopic traffic simulation model has been calibrated andentrance ramp congestion has been simulated under different traffic conditions. In comparisonwith no-control strategy in simulation, a model with an actual example has been verifiedabout the feasibility of this approach.