OPEN RESEARCH SYSTEM · CARLA 0.9.15
ByteDrive-Toy: From Pixels to Steering
Multisensor, two-frame temporal behavior-cloning driving research
Abstract Project summary
ByteDrive-Toy organizes autonomous-driving research into two learning stages. First, a frozen DINOv3 visual backbone supports joint 29-class semantic segmentation and metric depth estimation. Second, the learned perception representation aggregates three camera frustums, LiDAR voxels, and a rigidly aligned historical BEV into a forward-facing bird's-eye view, then jointly predicts spatial fields, road structure, traffic controls, multimodal trajectories, and behavior labels.
After training, the closed-loop runner connects the model to synchronous CARLA simulation: observation → two-frame inference → trajectory selection → pure-pursuit/PID control → next observation. It records episode terminal state, progress, diagnostics, and videos.
This is open, inspectable, still-evolving research infrastructure. The project describes implementations and results that exist in the repository and makes no product-style performance claims.
1 System Overview End-to-end pipeline
The repository covers the complete path from synthetic data generation to simulated vehicle execution. Its complexity comes from real dependencies between modules, not a collection of feature labels.
RGB · Depth · Semantics
Flow · LiDAR · Pose
29 semantic classes
Metric depth
Camera back-projection · voxels
Rigid two-frame alignment
Terminal state · progress
Diagnostics · video
Safety reranking · steering
Throttle · brake
Spatial fields · roads · traffic
8 trajectory modes
1.1 Heterogeneous data system Data System
A Python 3.7 worker drives CARLA 0.9.15 while a Python 3.12 collector orchestrates, encodes, and stores data. The runtimes exchange frames through a shared-memory arena. Sensors are normally recorded at 2 Hz and kinematics at 10 Hz; RGB uses H.265 and non-RGB data uses LMDB.
1.2 Perception pretraining Frozen visual backbone
The frozen DINOv3 ViT-S+/16 backbone returns complete token sequences from layers 3, 6, and 12. Their multiscale representation jointly supports 29-class semantic segmentation, symlog depth regression, and depth-range classification, then remains available to the driving model.
1.3 Geometry-aware BEV and joint planning Driving Model
Camera calibration maps patch centers and corners through sampled depths into 3D. Camera frustums, LiDAR voxels, and the preceding BEV meet in a forward 64 m × 64 m bird's-eye space. Eight learned mode tokens query intermediate BEV features while conditioned on the route target and planar ego velocity.
Risk, drivable, and trajectory-distribution fields
Lane classes, directed tangents, stop lines, and light state
8 modes × 20 waypoints at 10 Hz with confidence
8 behavior labels with auxiliary multitask supervision
2 Qualitative Results Repository-generated outputs
The following images and videos are produced directly by tools in the repository. They are experimental outputs used to inspect prediction quality, spatial alignment, and closed-loop behavior.
2.1 CARLA closed-loop execution Closed-loop Episodes
The top row shows the left/front/right cameras and vehicle state, the middle row shows spatial fields and road structure, and the bottom row shows every candidate trajectory and the executed winner.
3 Implementation Status Current repository scope
The table distinguishes working implementation from research goals that have not been implemented.
Multirate multisensor collection, shared memory, H.265 and LMDB
Implemented29 semantic classes, metric depth, frozen backbone, multitask training
ImplementedTwo-frame BEV, fields, roads, traffic, multimodal trajectory and behavior
ImplementedSynchronous inference, safety reranking, control, episode logs, and video
ImplementedNo reward, online sampling update, or closed-loop gradient
Not implemented4 Scope & Limitations Research boundary
The model learns offline from CARLA `BehaviorAgent` trajectories. “Closed loop” means model output acts on the simulator before the next observation; no reward optimization, policy update, or online gradient occurs.
- Limited data distribution. Current training and demonstrations focus on `Town02_Opt`, one expert style, and a fixed collection recipe.
- Two-frame temporal context only. The model uses one rigidly aligned historical BEV and has no long-term memory.
- Behavior cloning compounds error. Stopping, drifting, collision, and low route completion remain possible.
- CARLA simulation research only. Do not use this system for real roads, real vehicles, or safety-critical decisions.
5 Start from the Repository Documentation and source
The primary README documents tensor shapes, training, configuration, data formats, weights, closed-loop execution, and known limitations. This page is an introduction; the repository is the source of truth.
Apache-2.0 · Python 3.12 · CARLA 0.9.15