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Federated Reinforcement Learning for Intelligent Traffic Signal Control: A Privacy-Preserving Approach with Edge-Assisted Aggregation
Abstract— Urban traffic congestion costs the global economy over $1 trillion annually, necessitating intelligent traffic signal control (ITSC) solutions. Traditional centralized approaches face critical limitations: privacy violations from vehicle trajectory data sharing, prohibitive communication overhead, and scalability challenges in heterogeneous urban environments. This paper presents a federated reinforcement learning (FRL) framework for privacy-preserving traffic signal optimization. The proposed approach combines three innovations: edgeassisted aggregation weighting client contributions by local traffic density, FedProx regularization handling non-IID traffic distributions, and differential privacy. Evaluated on a 4×4 urban grid using SUMO simulation with four federated clients, our framework achieves 86.5% improvement in waiting time over 100 rounds, outperforms centralized Deep Q-Networks (DQN) by 56.6% at round 50 despite avoiding raw data access, and reduces communication overhead by 8,333. Results establish federated learning as a viable paradigm for scalable, privacy-compliant intelligent transportation systems with
superior performance to centralized approaches.