Study On The Method Of Multipoint Interlink Gating Control Based On Loop Detector Data

With the increasing development of urban economy and ecpanding scale, urban traffic congestion problem becomes more and more seriously, a growing number of signalization intersections are operated under oversaturated condition frequently, and the queue length of some roads even close to the link length during peak periods, which leads to spillovers. The role of spillovers in city street network is very significant, and it is already known for example that spillovers can lead to gridlock on ring roads and other network with "closed loop". In order to prevent the occurrence of spillovers and reduce the spatial and temporal fluctuations of the traffic congestion status. It is necessary to identify and dissipate spillovers accurate and timely, so as to avoid the negative influence either in complex urban systems or at intersections. As a result, this paper depends on loop detector data, studied on the characteristic research of bottleneck intersections firstly, then the multipoint interlink gating control model method is established, on the basis of bottleneck state identify. This paper mainly studied the following components:(1) Clear the basic concepts of bottlenecks and spillover, explain the traffic flow characteristics of bottleneck and bottleneck intersections. We start from the definition of oversaturated, define the traffic state on a road, where spillover has occurred as the bottleneck state. then analysis the cause of the oversaturated state and the characteristic of oversaturated traffic, introduces some special properties of the bottleneck intersections, including the related concept of bottlenecks and the generation mechanism of bottleneck intersections. That can provide theoretical basis for bottleneck identification and bottleneck control optimization.(2) The method of Bottleneck state identify. Select queue length as the major indexes of the identify of spillovers. First, the method of bottleneck identification based on maximum queue length is proposed, and analyzes the advantages and disadvantages of the method; Then on the basis of the above, we put forward the method based on SPM model to identify the spillovers, and verified the feasibility of this method by VISSIM simulation:which can solve the problems of the can’t be calculated when queue length is more than detector, but this method can’t estimate the queue length, and it needs a complete traffic information, including the signal control scheme of the upstream and downstream、the traffic flow information of all approachs’ lane. But in the actual urban road network, the detector layout rate is very low, which cann’t meet the actual demand of the SPM method; So for better identify the bottleneck state in urban road network, we introduces the basic concept of bottleneck detector, and put forward the bottleneck state recognition method based on the information of bottleneck detector, which can both reduce the basis of traffic information and enhance the bottleneck of the real time state recognition.(3) The multipoint interlink gating control model. we present an influence rate model for upstream links of the bottleneck link and a share ratio model for the downstream links. With known threshold values for the influence rate and share ratio, we propose a rule and process for selecting the intersections that should be included in the sub-area of the gating control. Then we determinetotal capacity adjustments for the incoming and outgoing streams of bottleneck links. Under the measures, the queue can be dissipated to a permissible length within a given period of time. After that, the apportion models for the total adjustments among different paths and links are presented. Therefore, the correlation coefficients of the traffic flows are between the bottleneck link and the other links. Next, we ascertain the capacity decrements and increments for the gated and benefiting streams. The optimization schemes are defined so as to calculate splits for the gated and benefiting intersections. Finally, we evaluate the advanced method using a VISSIM simulation based on the actual road network of hangzhou.