Modeling And Numerical Simulation Of Urban Traffic Flow Based On Intelligent Traffic System

Based upon the classical car-following theory and the cooperative adaptive cruise control(CACC)strategy,some modified car-following models are proposed to suppress traffic jams.The stability condition for those improved models are obtained via the linear stability theory.Numerical simulation is carried out to illustrate the advantages of our model with the new control signal.The summarization of this paper is as follows:(1)In this part,a car-following model with the consideration of lateral effect is constructed.An improved control signal with considering more comprehensive information is introduced according to the feedback control theory.The stability conditions with control signal or not are derived.Numerical simulations are carried out to illustrate the advantage of the modified model with and without the control signal.(2)Based on the advanced intelligent transportation systems(ITS),a modified car-following model with considering variable safety distance is proposed to suppress traffic jams.Considering the relative velocity,relative optimal velocity,and the difference between safety distance and headway,a comprehensive control scheme is constructed according to the feedback control theory.The stability condition for the improved model is obtained via the linear stability theory and the simulations are carried out to illustrate the advantages of the presented model.(3)A comprehensive control system which can handle three traffic conditions to guarantee driving efficiency and safety is designed by using three CACC models.In this control system,some vital comprehensive information,such as multiple preceding cars' speed differences and headway,variable safety distance(VSD)and time-delay effect on the traffic system has been investigated.Local and string stability criterion for the velocity control(VC)model and gap control(GC)model are derived via linear stability theory.The simulation results show that the proposed model can improve driving efficiency and suppress traffic congestion.