Traffic Signal Cycle Control with Centralized Critic and Decentralized Actors under Varying Intervention Frequencies

TL;DR

This paper presents a novel traffic signal control method that combines centralized critic and decentralized actors, effectively managing varying control intervals to reduce congestion and improve traffic flow.

Contribution

It introduces a joint phase control approach with adjustable all-phase actions and a hybrid centralized-decentralized framework, enhancing stability and performance at different control frequencies.

Findings

Outperforms existing methods at high control intervals

Demonstrates robustness across synthetic and real-world data

Improves traffic flow and reduces congestion effectively

Abstract

Traffic congestion in urban areas is a significant problem, leading to prolonged travel times, reduced efficiency, and increased environmental concerns. Effective traffic signal control (TSC) is a key strategy for reducing congestion. Unlike most TSC systems that rely on high-frequency control, this study introduces an innovative joint phase traffic signal cycle control method that operates effectively with varying control intervals. Our method features an adjust all phases action design, enabling simultaneous phase changes within the signal cycle, which fosters both immediate stability and sustained TSC effectiveness, especially at lower frequencies. The approach also integrates decentralized actors to handle the complexity of the action space, with a centralized critic to ensure coordinated phase adjusting. Extensive testing on both synthetic and real-world data across different intersection types and signal setups shows that our method significantly outperforms other popular techniques, particularly at high control intervals. Case studies of policies derived from traffic data further illustrate the robustness and reliability of our proposed method.