Gating Control for a Single Bottleneck Link Based on Traffic Load Equilibrium

Abstract

The purpose of this paper is to improve the intelligence and universality of the classical method for gating control in the SCOOT system. First, we introduce a method to identify spillovers, and use the occupancy threshold for spillover recognition to trigger this special control logic. Second, the interrelationship of the traffic flows among adjacent traffic links is analyzed. Accordingly, 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. Third, we determine total 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. The results show that a new control method brings significant and positive effects to the bottleneck link itself and to the entire test area.