def reset(self):
        """
        Agent manager is really initialized after the BaseVehicle Instances are created
        """
        self.random_spawn_lane_in_single_agent()
        config = self.engine.global_config
        self._delay_done = config["delay_done"]
        self._infinite_agents = config["num_agents"] == -1
        self._allow_respawn = config["allow_respawn"]
        super(VehicleAgentManager, self).reset()

        Agent manager is really initialized after the BaseVehicle Instances are created
        
metadrive/manager/agent_manager.py