Two-stage Perimeter Signal Control with Spillback-aware Set-points based on Network Buffer Capacity

Abstract

Managing cordon queues and spillback is one of the major challenges in perimeter control (PC). To address this issue, this study proposes a two-stage framework for signal optimization at perimeter intersections. In Stage I, the concept of network buffer capacity is introduced, together with a calibration method. Based on this concept, the optimal gated inflows are determined through a spillback-aware multi-objective model to jointly account for network- and cordon-level control objectives. The weight coefficients in the model are adaptively adjusted according to the real-time traffic states. In Stage II, the green durations and phase structures of each perimeter intersection are simultaneously optimized using a group-based signal control approach. Experiments show that, compared with traditional feedback PC strategies, the proposed framework significantly mitigates cordon spillback while preventing network gridlock. The results also highlight the necessity of jointly optimizing phase structures and green durations under time-varying traffic conditions.