Research On Cooperative Control Stratergy Of Expressway Under Emergency Evacuation

With the acceleration of urbanization,the number of cars has increased rapidly,urban traffic congestion has become increasingly serious,and the construction and control of expressways have attracted widespread attention.In recent years,many scholars have proposed ramp control,variable speed limit control,and coordination of multiple controls in control strategies.Traffic control related research has also made a series of progress and results in solving urban traffic congestion problems.However,in the context of emergency evacuation,the control objectives and traffic flow characteristics change,so that the current control strategy cannot fully meet the needs of emergency evacuation.Therefore,this article takes the ramp control of urban expressways in emergency evacuation scenarios as the research object,and develops traffic control strategies that adapt to emergency evacuation scenarios through the analysis and exploration of control effect evaluation index construction,traffic flow model expansion,case analysis and other related content Research work and evaluate its control effect.This article starts from the influence of the four aspects of emergency evacuation event type,emergency evacuation scale,emergency evacuation method,and emergency evacuation scope on the formulation of control strategies,determines the research scenario of this article,and partitions the evacuation area according to the zoning standard,and develops a regional management and control strategy,And analyze the possible consequences of expressway traffic flow operation under the current control strategy.Based on this,this paper constructs an expressway multi-ramp cooperative control model based on evacuation risk and designs an algorithm to solve it.In terms of objective function,starting from the commonly used control effect evaluation indicators,considering the number of vehicles exposed on the road section,the length of exposure,and the possibility of substantial harm from exposure to hazardous environments,construct the control effect evaluation indicators based on evacuation risks;Regarding the macroscopic traffic flow model,considering the superiority of the Cellular Transmission Model(CTM)in simulating the emergency evacuation traffic flow operation,the CTM is selected and the ramp control and risk characteristics are considered to improve the classic model,and then in the CTM Based on the introduction of the Model Predictive Control(MPC)framework,a multi-ramp control model based on MPC was established,and a differential evolution algorithm was designed to optimize the problem.Finally,the design case carried out simulation experiments and comparative analysis on the proposed collaborative control strategy.The open source urban mobility simulation software SUMO was used for simulation design and secondary development.The output control strategy controls the signal and compares the output in different scenarios.The changes in traffic flow parameters,queue length,evacuation time and the risk value of the objective function show that the established control strategy is effective.This study provides a theoretical basis for the research of Expressway collaborative control strategy in emergency evacuation situation,expands the application scenarios of traffic management and control technology,and provides method reference for reducing evacuation risk and ensuring evacuation safety,which has certain theoretical and practical significance.