Multi-agent Reinforcement Learning for Regional Signal control in Large-scale Grid Traffic network

Adaptive traffic signal control with Multi-agent Reinforcement Learning(MARL) is a very popular topic nowadays. In most existing novel methods, one agent controls single intersections and these methods focus on the cooperation between intersections. However, the non-stationary property of MARL still limits the performance of the above methods as the size of traffic networks grows. One compromised strategy is to assign one agent with a region of intersections to reduce the number of agents. There are two challenges in this strategy, one is how to partition a traffic network into small regions and the other is how to search for the optimal joint actions for a region of intersections. In this paper, we propose a novel training framework RegionLight where our region partition rule is based on the adjacency between the intersection and extended Branching Dueling Q-Network(BDQ) to Dynamic Branching Dueling Q-Network(DBDQ) to bound the growth of the size of joint action space and alleviate the bias introduced by imaginary intersections outside of the boundary of the traffic network. Our experiments on both real datasets and synthetic datasets demonstrate that our framework performs best among other novel frameworks and that our region partition rule is robust.