discrepancy between the planned duration and the actual testing time

[Feiju112]

In the highway_env environment, I have designed the following:
def default_config(cls) -> dict:
cfg = super().default_config()
cfg.update({
"simulation_frequency": 5,
"policy_frequency": 5,
"lanes_count": 3,
"vehicles_count": 30,
"duration": 30, # [s]
"ego_spacing": 1.5,
})
return cfg
Here, the duration is set to 30 seconds. However, when validating the trained PPO policy, the recorded result consistently lasts only 15 seconds, despite no collisions that would terminate the simulation. The following is the testing and rendering code:

Run the trained model and record video

env = gymnasium.make("highway-fast-v0", render_mode="rgb_array")
env = RecordVideo(env, video_folder="./ppo_videos", episode_trigger=lambda e: True)
env.unwrapped.set_record_video_wrapper(env)
env.configure({"simulation_frequency": 15}) # Higher FPS for rendering
model = PPO.load("highway_ppo/model", env=env)
for videos in range(20):
done = truncated = False
obs, info = env.reset()
while not (done or truncated):
action, _states = model.predict(obs, deterministic=True)
obs, reward, done, truncated, info = env.step(action)
env.render()
env.close()
Please provide the specific issue. Thank you!!!