Study On Single-point Signal Control Method Based On Time-space Saturaton

With the rapid development of urban economy, residents’ travel demand continues toimprove, which Bring a certain amount of pressure and negative effects to the city traffic.At present, traffic congestion is the main issues of universal concern, to bring a certainimpediment to the development of the city and some impacts on people’s daily life and trips.Therefore, certain measures must be taken to alleviate traffic congestion, in order toimprove the quality of the urban traffic environment. Intersection is the key node of theurban transport network, which plays a vital role to the traffic operations of the entire citynetwork. Urban traffic congestion are often rooted in a local area, The intersections are themain zones, If we could find traffic congestion, and take reasonable signal control, whichcan effectively avoid the congestion proliferation and play Important role to the urbantraffic control. Therefore, the reasonable control of the intersection is a key entry point toimprove traffic congestion. At present, the single point of intersection control in the signalcontrol is still a dominant position, can effectively solve the traffic chaos and otherphenomenas, which have a great significance to improve the capacity of the entire citynetwork.It is proposed research’s orientation and related technologies routes on the basis of theresearch status at home and abroad in this paper. First of all, describing some basicparameters of single-point signal control intersection (green ratio signal cycle, signal phase,saturation flow and so on)、indexes of effect evaluation（delay, queue length, capacity）,establish the delay model according to the Webster theory, and summarize the calculationidea of the saturation and the intersection’s capacity. Based on this, to establish the queuelength calculation model adopting separately traditional traffic flow model, the traffic wavetheory, and probabilistic methods. Through comparative analysis, The conclusion isobtained, which dynamic queue length’s calculation in the light of traffic wave theory hascertain advantages. Secondly, analyze queuing impact the length of the intersection indetail application of traffic wave theory, systematically introduces three levels of theintersection: Smooth, mild congestion and serious congestion. Based on this, calculate thequeue length. First of all, we can see that Greenshields model suitable for describing thestatus of little traffic density for the traffic, but other methods should be used for greaterdensity of traffic flow, here calculating the wave with the Grenberg transport model, Andcorrecting the transport wave model with the Grenberg model, which makes it suitable for practical computing demands. Then putting forward the critical value of the secondqueuing and calculation method of the queuing dissipation length according to the revisedtraffic wave’s velocity and the traffic wave’s propagation characteristics at the intersection,in order to provide data support for next signal control algorithm research. once more，Putting forward single-point signal control intersection’ method based on temporal andspatial saturation though fully considering time and space resources utilization of theintersection, and improve the Webster model, taking into account the affect of the queuingdissipation length and section of the length to the signal timing. In the temporal and spatialsaturation distribution of green time constraint conditions, establish a single point of signalcontrol model which is based on temporal and spatial saturation, and calculate parametersaccording to1stOpt, and comparison with the Webster method, verify the validity of themodel of the signal control by an example.