Impact of traffic management center functionality on speed harmonization in urban networks under mixed traffic environments
The study evaluated three traffic management center (TMC) configurations—centralized, hybrid, and decentralized—for CAV speed harmonization in urban networks using multi-agent reinforcement learning across varied data-sharing levels and fleet sizes of 20 and 40 vehicles, including validation in the TAVF-Hamburg network. Fully centralized training and execution produced the most stable improvements, whereas hybrid configurations suffered severe performance drops under limited data conditions with smaller CAV fleets but recovered as fleet sizes doubled. Fully decentralized independent learners demonstrated inconsistent performance across all data and fleet conditions.
Why it matters — This reveals that traffic management authority and data-sharing capabilities cannot be designed independently, proving that centralized control is crucial for stabilizing traffic flows during early, low-penetration autonomous vehicle deployments when network data is sparse.
Caveat: The findings rely on microsimulations with low counts of simultaneously controlled vehicles, which may not capture dynamics in saturated, real-world networks with high CAV penetration rates.