Modeling And Simulation Of Mixed Traffic Flow At Signal-Controlled Intersections Under The Environment Of Connected Vehicles

Now and for a long time to come,there will be a mix of conventional manually driven vehicles(MVs)and CACC-equipped vehicles(CVs)on the road.It is necessary to study the mixed traffic flow of CVs and MVs.Based on cellular automata model,this thesis simulates and studies the operation characteristics of mixed traffic flow composed of MVs and CVs at signalized intersections.Firstly,the single-lane mixed flow is modeled and simulated.Considering the interaction of MVs and CVs and the influence of signal lights on the motion behavior of CVs,a single-lane cellular automaton model of mixed flow is established.Simulation analysis shows: The adaptive cruise control capability of CVs and the communication between CVs(vehicle-to-vehicle communication,namely V2 V communication)contribute to the improvement of traffic efficiency;Vehicle-toinfrastructure(V2I)communication between CVs and the traffic signal has both promoting and inhibiting effects on traffic efficiency,and the final effect is related to the signal cycle.This thesis also studies the operation of mixed flow in the contraflow left-turn lane.Considering the number of vehicles ahead,the motion state of the front vehicle,the status of signal lights and the signal period when the vehicle is driving to the opening area,a decision-making procedure of whether to bypass or not is developed for the CACC system.The simulation results show that the CACC system can improve the traffic efficiency of left-turn vehicles.The length of the borrowable area and the opening time of the bypass signal light have a greater impact on the throughput of left-turn vehicles.The proportion of U-turn vehicles will also have a greater impact on the left-turn traffic flow.As the proportion of Uturn vehicles gradually increases,the left-turn traffic flow decreases significantly.When the proportion of U-turn vehicles is constant,the longer the green light duration of the U-turn signal,the greater the left-turn traffic flow.In addition,this thesis also studies the problem of stop/go decision during the yellow light period.Based on the aforementioned mixed-flow following rules,this thesis models and simulates the stop/go decisionmaking process of MVs during the yellow light considering vehicle type,vehicle position in traffic flow,distance between vehicle and stop line,remaining time of yellow light,type of adjacent vehicles,the impact of CVs on MVs,and the coordinated decision-making of CVs.And a stop/go decision program is developed for CACC system based on the principle of quick pass,reduce delay and ensure comfort as much as possible.The results show that: the introduction of CVs can improve traffic efficiency during yellow lights.As the market penetration rate of CVs increases,the passage rate of the entire mixed flow gradually increases,and the yellow light flow rate first increases and then decreases,reaching the maximum value at market penetration rate of 0.6.