Agents

Agents is a list of Agent class objects. Agent class is the controller of traffic signals at single or multiple intersections. It can provide information of observation, phase, reward or others with get_ob, get_phase, get_reward. And it can also give lane level metric through get_queue, get_delay. The Agent class also gives action back to the simulator through get_action. Currently, LibSignal supports Non-RL based Agent, RL based Agent, Agent imported from other lib and Agent that users customized.

BaseAgent

BaseAgent class is used for creating a base agent and base methods. All the Agent classes must inherit BaseAgent class and override get_ob, get_reward, get_action and get_action_prob methods.

RLAgent

RLAgent class is used for creating an RL-based agent. It would create Generators of observation, phase, reward, queue and delay. It must recreate Generator in __init__ and reset methods if an RL-based agent has different settings for observation, phase, reward, queue and delay.

Default Generator Settings

• Observation: the default observation generator of an agent is lane_count, defined as the number of running vehicles on each lane.

• Phase: the default phase generator of an agent is phase, defined as the current phase of the intersection.

• Reward: the default reward generator of an agent is lane_waiting_count, defined as the number of waiting vehicles(speed less than 0.1m/s) on each lane.

• Queue: the default queue generator of an agent is lane_waiting_count.

• Delay: the default delay generator of an agent is lane_delay, defined as the average difference between the current speed of the vehicle and the maximum speed limit of this lane over all vehicles.

Imported Agent and Customized Agent

For Imported Agent and Customized Agent, details can be found in Customize Agent.