Please see here: https://github.com/flow-project/flow/blob/master/flow/benchmarks/figureeight1.py
You can iteratively add several human-driven vehicles first and then some RL vehicles next.
for i in range(7):
vehicles.add(
veh_id="human{}".format(i),
acceleration_controller=(IDMController, {
"noise": 0.2
}),
routing_controller=(ContinuousRouter, {}),
car_following_params=SumoCarFollowingParams(
speed_mode="obey_safe_speed",
),
num_vehicles=1)
vehicles.add(
veh_id="rl{}".format(i),
acceleration_controller=(RLController, {}),
routing_controller=(ContinuousRouter, {}),
car_following_params=SumoCarFollowingParams(
speed_mode="obey_safe_speed",
),
num_vehicles=1)