/Schedule-Driven Coordination for Real-Time Traffic Network Control

Schedule-Driven Coordination for Real-Time Traffic Network Control

Xiao-Feng Xie, Stephen Smith and Gregory Barlow
Conference Paper, Proceedings 22nd International Conference on Automated Planning and Scheduling, Atibaia, Sao Paulo, Brazil, June 2012., June, 2012

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Real-time optimization of the dynamic flow of vehicle traf-fic through a network of signalized intersections is an im-portant practical problem. In this paper, we take a decentral-ized, schedule-driven coordination approach to address the challenge of achieving scalable network-wide optimization.To be locally effective, each intersection is controlled inde-pendently by an on-line scheduling agent. At each decision point, an agent constructs a schedule that optimizes move-ment of the observable traffic through the intersection, and uses this schedule to determine the best control action to take over the current look-ahead horizon. Decentralized coordina-tion mechanisms, limited to interaction among direct neigh-bors to ensure scalability, are then layered on top of these asynchronously operating scheduling agents to promote over-all performance. As a basic protocol, each agent queries for newly planned output flows from its upstream neighbors to obtain an optimistic projection of future demand. This projec-tion may incorporate non-local influence from indirect neigh-bors depending on horizon length. Two additional mecha-nisms are then introduced to dampen “nervousness” and dy-namic instability in the network, by adjusting locally deter-mined schedules to better align with those of neighbors. We present simulation results on two traffic networks of tightly-coupled intersections that demonstrate the ability of our ap-proach to establish traffic flows with lower average vehicle wait times than both a simple isolated control strategy and other contemporary coordinated control strategies that use moving average forecast or traditional offset calculation.

BibTeX Reference
author = {Xiao-Feng Xie and Stephen Smith and Gregory Barlow},
title = {Schedule-Driven Coordination for Real-Time Traffic Network Control},
booktitle = {Proceedings 22nd International Conference on Automated Planning and Scheduling, Atibaia, Sao Paulo, Brazil, June 2012.},
year = {2012},
month = {June},