Coordinated On-Ramp Metering Of Urban Expressway Based On Real-Time OD Information

Urban expressway is the main artery of urban traffic.However,the problem of expressway congestion is increasing seriously with the increase of traffic demand.On-ramp metering is an important means to alleviate expressway congestion.Traditional on-ramp control method cannot meet needs with the development of technologies such as the Internet of Vehicles.Therefore,it is of great significance to explore the coordinated on-ramp metering based on the characteristics of traffic control in the era of Internet of vehicles.This paper explores the control strategy of expressway on-ramp from the perspective of system.Firstly,the necessity of on-ramp metering and the demand analysis of coordinated on-ramp metering are carried out.Then,the research status of coordinated on-ramp metering is analyzed.On this basis,the integrated framework and application scope of coordinated on-ramp metering strategy are proposed.Different from previous studies,the coordinated on-ramp metering strategy proposed in this paper covers a wider range.It involves the coordination of multiple on-ramps on the expressway and how to coordinate the on-ramp and intersection based on the coordinated multiple on-ramps metering.According to the overall framework of coordinated on-ramps control strategy determined in this paper,the signal control of on-ramp adjacent intersection should cope with coordinated on-ramps metering.Firstly,the characteristics of on-ramp adjacent intersections are analyzed.According to the analysis results,this paper abstracts the control problem of on-ramp adjacent intersection into a multi-objective optimization problem.The main objective method is selected to solve the problem according to the actual situation.An on-ramp adjacent intersection control algorithm suitable for coordinated on-ramps metering is proposed.The VISSIM simulation is applied to analyze the example and compare with the classical method.The results show that under the same ramp metering rate the proposed control scheme performs better than the uncoordinated conventional calculation scheme on the whole.This shows the proposed control algorithm is effective.Combined with the real-time OD information of vehicles and the QHM heuristic control framework,OD-QHM algorithm is proposed for coordinatedmultiple on-ramps metering.This control algorithm can not only alleviate the current bottleneck breakdown of expressway,but also avoid new bottleneck breakdown caused by the implementation of scheme.The results show that the effectiveness and stability of the OD-QHM algorithm is better than the widely used ALINEA algorithm.Therefore,it is feasible to introduce the real-time OD information into traffic control.