CoPhy

Distill to Think, Foresee to Act:
Cognitive-Physical Reinforcement Learning for Autonomous Driving

NeurIPS 2026

Yang Wu1Qiang Meng†Zhaojiang Liu3Youquan Liu4Jian Yang1,2Jin Xie2,*
1 PCA Lab, Nanjing University of Science and Technology2 Nanjing University3 Shanghai Jiao Tong University4 Fudan University

† Independent researcher.   * Corresponding author.

Abstract

Current end-to-end autonomous driving models are fundamentally constrained by the behavioral cloning ceiling of imitation learning. While reinforcement learning offers a path to smarter autonomy, it demands two missing pieces of infrastructure: (1) a cognitive foundation that understands traffic semantics and driving intent, and (2) a foresighted physical environment that can anticipate the consequences of candidate actions.

To this end, we propose CoPhy, a Cognitive-Physical reinforcement learning framework for autonomous driving. To distill to think, we distill VLM knowledge into the BEV encoder and then discard the VLM entirely, retaining cognitive ability at zero inference cost while releasing the cognitive channel as a pluggable interface for optional human language commands. To foresee to act, we build an auto-regressive BEV world model that explicitly predicts future semantic maps conditioned on candidate actions, serving as an interpretable physical sandbox from which safety metrics are directly derived.

Built upon this dual infrastructure, we optimize the driving policy via GRPO with a novel dual-reward mechanism: a physical reward derived from BEV rollouts enforces hard safety constraints, while a cognitive reward from a language-aligned scorer ensures intent compliance. Extensive experiments demonstrate that CoPhy not only achieves state-of-the-art results on NAVSIM v1 and v2 benchmarks, but also enables safer driving via cognitively informed scene compliance and flexible intent control through user-defined language instructions.

Distill to Think. Foresee to Act.

Cognitive priors, predictive physical reasoning, and dual-reward policy optimization in one driving framework.

CoPhy framework: cross-modal cognitive distillation, action-conditioned BEV world-model rollout, and cognitive-physical reinforcement learning.
Overview of CoPhy. VLM knowledge enriches the BEV representation, while predicted future semantic maps support physical reward evaluation.

01 / DISTILL

Cognitive prior distillation

Transfer VLM knowledge into the BEV encoder to capture traffic semantics and driving intent without retaining the VLM at inference.

02 / FORESEE

Predictive world model

Roll out future semantic BEV maps conditioned on candidate actions, making their predicted physical consequences explicit.

03 / OPTIMIZE

Cognitive-physical RL

Optimize the driving policy with GRPO, combining physical safety rewards with cognitive intent-alignment rewards.

Video Demonstrations

Explore CoPhy's driving visualizations across diverse road conditions. Select a video to play; starting another pauses the previous clip.

Driving Demos Across Diverse Road Conditions

These driving visualizations showcase turning, lane keeping, and car following in varied environments, including rainy weather, construction zones, winding roads, busy intersections, and congested traffic with limited visibility. Red trajectories represent model predictions, while green trajectories represent the ground truth (GT).

Sharp Turning in Rain
A large steering maneuver in rainy conditions.
Driving Through a Construction Zone
Lane keeping and turning through a road construction area.
Continuous Turns on a Winding Road
Following successive curves with continuous steering adjustments.
Turning at a Busy Intersection
A turning maneuver at an intersection with busy traffic.
Car Following in Congested Traffic
Following the vehicle ahead along a crowded road segment.
Successive Curves on an Undulating Road
Driving through continuous bends over changing road elevations.
Car Following with Limited Visibility
Following traffic on a congested road with a restricted view ahead.
Turning on a Tree-Lined Road
A turning maneuver along a tree-shaded road segment.

Scene-Aware Driving

These examples illustrate driving informed by scene semantics, including traffic signals, intersection layouts, sidewalks, bicycle lanes, and speed limits. CoPhy combines cognitive scene understanding with physical reasoning to guide driving behavior in context.

Crossing on Green in Sunny Weather
Proceeding through a green-light intersection in sunny conditions.
Slowing Down at a T-Junction
Navigating a T-junction at low speed.
Following Traffic on Green Beside a Sidewalk
Following the vehicle ahead through a green light while driving close to a sidewalk.
Following a Tree-Lined Curve
Driving through a bend along a tree-shaded road.
Turning Beside a Bicycle Lane
Executing a turn alongside a bicycle lane.
Speed-Limited Turning on a Service Road
Negotiating a turn on a service road while observing the speed limit.

Future BEV Prediction

Human Commands Shape Driving Trajectories

Human language commands allow CoPhy to adapt its planned driving trajectories to different driving intents.

Examples of human language commands changing CoPhy's planned driving trajectories.

BibTeX

@article{wu2026distill,
  title={Distill to Think, Foresee to Act: Cognitive-Physical Reinforcement Learning for Autonomous Driving},
  author={Wu, Yang and Meng, Qiang and Liu, Zhaojiang and Liu, Youquan and Yang, Jian and Xie, Jin},
  journal={arXiv preprint arXiv:2605.21139},
  year={2026}
}