Research On Control Methods Of Signalized Intersections Under Queue Length Restriction

There are many reasons for the cause of the traffic jam, such as the rapid increase of the vehicle,the disordered traffic order,irrationality of the road design,low lever of traffic manage and occasional traffic accident and so on. Along with the sostenuto increase of the amount of car and the complexity of road network, the probability traffic jam occurs become ,the duration become longer and longer, the incidence become wider and wider , the manpower and material resources that used for resolving the jam problem become huger and huger.For essential, it is the imbalance between traffic demand and traffic supply that lead to the occasional jams. The location that a jam occurs usually locates a traffic bottleneck and the time usually be the fastigium resident go out and in. when traffic demand continuously rise, there would appear long queue and partial jam. The whole traffic network would be affected and the queue would trace to the up-intersection if there isn't some measures to take in time to eliminate the partial jam. The crossed traffic would be hold up and the traffic jams would diffuse continuously to up network when the vehicle in queue reaches the up-intersection. The continuous pervasion of the traffic jams above-mentioned can be intitule to traffic domino phenomenon because it is similar to the continuous collapse of the domino. It is the traffic flow's influencing each other cause the traffic domino phenomenon which can lead to serious traffic paralysis. This degree paper's idea is based on how to prevent the above-mentioned phenomenon and the whole paper can be divided to five section:Main content of the first chapter is study background and study significance of this paper.Main content of the second chapter is the basic theory. At first it introduce the control parameter and function used for project choice: there are many parameters that can be used for estimating the control project, such as the delay tine,queue length,fuel consuming and so on. In fact, we should choice proper parameters being the estimating gist base on the actual traffic state because we usually can't make all the control parameter to minimum at one time. According to the main content of this paper, we should choice queue length for the estimating parameter so that the queue at each road can keeps up a"safe threshold".Second it introduce the study actuality of the queue length calculating.The queue length estimating model which is one of the foremost content is established in the third chapter. For controlling by queue length, first we must gain the queue position momently, then estimate if the queue would trace to the up-intersection. Traffic wave theory is used to create real-time queuing model in this chapter, and Gelinbei model which is suitable for describe high-density traffic flow is used to modify it. In the new model, the independent variable is the density of the traffic flow. The analysis revealed that sections of the state of traffic flow can be divided into three types : normal state,blocking state and the state vehicle run from starting to crossing stopping line. Subsequently there is a presentation of the three states.The main content of the chapter four is the queue control strategy and control method. Signal control based on queue constraining is "mandatory"process and the aim is to make the queue length to keeping steady. All this based on expense of the capacity of some phase, therefore we must not only ensure that the signal can not regulate frequent opening, but also makes the signal adjust smoothly. The queuing constrained control began at the triggering of the queue length threshold, the signal state to the target signal timing changes After adjustment the change of the queue length become more stable. The queue constrained control is over When the queue length below a certain threshold value.In the fifth chapter, there is a summing-up and expectation of the paper.