Learning to drive from a world on rails
TLDR
Proposes a model-based driving policy with a world-on-rails assumption, outperforming IL and RL on CARLA and ProcGen benchmarks.
Reasoning
The paper introduces a novel 'world on rails' assumption that simplifies learning by factorizing dynamics into a non-reactive world model and a compact forward model, allowing effective training from pre-recorded logs. Strengths include strong empirical results on standard benchmarks and sample efficiency, but the assumption may limit applicability to environments where agent actions significantly affect the world.
Read-first score
Read-first score 51.7, weighted from topical fit, citation, graph, method, reproducibility, and recency signals. Original total remains 38.
Field roles
Rank sensitivity
Stability: volatile; rank range: 174.
Keyword Scores
Deep Analysis
Innovations
- World-on-rails assumption: agent's actions do not influence the environment, simplifying learning from pre-recorded logs.
- Factorizing dynamics into a non-reactive world model and a low-dimensional forward model of the ego-vehicle.
- Using tabular dynamic-programming on Bellman equations to compute action-values for training trajectories, then supervising a vision-based policy.
Methodology
A model-based approach learns a vision-based driving policy from pre-recorded logs under the assumption that the world is on rails, meaning the environment is non-reactive. The dynamics are factorized into a static world model and a compact ego-vehicle forward model, and action-values are computed via tabular dynamic programming on the Bellman equations to supervise the policy.
Key Results
The policy outperforms imitation learning, model-based, and model-free reinforcement learning on CARLA NoCrash, and is an order of magnitude more sample-efficient than state-of-the-art model-free RL on ProcGen navigational tasks.
Limitations
- Relies on the world-on-rails assumption, meaning the environment is treated as non-reactive during training; applicability may be limited when logs do not capture full environmental interactions.