Vision-Language-Action (VLA) models have recently emerged in autonomous driving, with the promise of leveraging rich world knowledge to improve the cognitive capabilities of driving systems. However, adapting such models for driving tasks currently faces a critical dilemma between spatial perception and semantic reasoning. Consequently, existing VLA systems are forced into suboptimal compromises: directly adopting 2D Vision-Language Models yields limited spatial perception, whereas enhancing them with 3D spatial representations often impairs the native reasoning capacity of VLMs. We argue that this dilemma largely stems from the coupled optimization of spatial perception and semantic reasoning within shared model parameters. To overcome this, we propose UniDriveVLA, a Unified Driving Vision-Language-Action model based on Mixture-of-Transformers that addresses the perception-reasoning conflict via expert decoupling. Specifically, it comprises three experts for driving understanding, scene perception, and action planning, which are coordinated through masked joint attention. In addition, we combine a sparse perception paradigm with a three-stage progressive training strategy to improve spatial perception while maintaining semantic reasoning capability. Extensive experiments show that UniDriveVLA achieves state-of-the-art performance in open-loop evaluation on nuScenes and closed-loop evaluation on Bench2Drive. Moreover, it demonstrates strong performance across a broad range of perception, prediction, and understanding tasks, including 3D detection, online mapping, motion forecasting, and driving-oriented VQA, highlighting its broad applicability as a unified model for autonomous driving. Code and model have been released at https://github.com/xiaomi-research/unidrivevla
Figures & tables
Figure 1: Comparison of VLA paradigms for autonomous driving. (a) Vanilla 2D VLA provides strong semantic reasoning but limited spatial perception. (b) 3D-enhanced VLA improves spatial perception but may degrade semantic reasoning. (c) UniDriveVLA decouples understanding, perception, and action with the Mixture-of-Transformers architecture, achieving both.
Figure 2: Analysis of representation interference and model performance. (a) Cosine similarity between LLM tokens and perception tokens across layers. In the shared-weight decoder, the similarity progressively increases toward 1, indicating feature collapse into nearly identical representations, whereas MoT maintains low similarity and preserves task decoupling. (b) Performance comparison. By mitigating optimization conflicts, UniDriveVLA consistently outperforms the shared-weight baseline across perception, reasoning, and planning metrics.
Figure 3: Architecture overview of UniDriveVLA. UniDriveVLA adopts a Mixture-of-Transformers architecture with three specialized experts for driving understanding, scene perception, and action planning. By decoupling heterogeneous tokens into dedicated experts and coordinating them through masked joint attention, the model mitigates optimization conflicts and unifies understanding, perception, and planning within a single framework.
Figure 4: Illustration of Masked Joint Attention.
Method
Open-loop Metric
Closed-loop Metric
Avg. L2 ↓
Driving Score ↑
Success Rate (%) ↑
Efficiency ↑
Comfortness ↑
AutoVLA † [NeurIPS25] [ 120 ]
-
78.84
57.73
146.93
39.33
SimLingo † [CVPR25] [ 77 ]
-
85.94
66.82
244.18
25.49
R2SE † [T-PAMI26] [ 56 ]
-
86.28
69.54
243.89
23.26
AD-MLP [arXiv23] [ 112 ]
3.64
18.05
0.00
48.45
22.63
VAD [ICCV23] [ 42 ]
0.91
42.35
15.00
157.94
46.01
Table 1: Open-loop and closed-loop planning results on Bench2Drive. Avg. L2 is computed over predictions within a 2-second horizon at 2 Hz. † Models trained on PDM-Lite, which provides higher-quality expert demonstrations than Think2Drive. Bold numbers indicate the best results among methods trained without PDM-Lite.
Method
Ability (%) ↑
Merging
Overtaking
Emergency Brake
Give Way
Traffic Sign
Mean
AD-MLP [arXiv23] [ 112 ]
0.00
0.00
0.00
0.00
4.35
0.87
UniAD [CVPR23] [ 29 ]
14.10
17.78
21.67
10.00
14.21
15.55
VAD [ICCV23] [ 42 ]
8.11
24.44
18.64
20.00
19.15
18.07
ThinkTwice [CVPR22] [ 37 ]
13.72
22.93
52.99
50.00
47.78
37.48
DriveAdapter [ICCV23] [ 36 ]
14.55
22.61
54.04
50.00
50.45
38.33
Table 2: Multi-ability results of end-to-end autonomous driving methods on Bench2Drive.
Method
ST-P3 metrics
UniAD metrics
LLM
L2 (m) ↓
Collision (%) ↓
L2 (m) ↓
Collision (%) ↓
1s
2s
3s
Avg.
1s
2s
3s
Avg.
1s
2s
3s
Avg.
1s
2s
3s
Avg.
Methods with Ego Status
ST-P3* [ 28 ]
1.33
2.11
2.90
2.11
0.23
0.62
1.27
0.71
-
-
-
-
-
-
-
-
-
VAD* [ 42 ]
0.17
0.34
0.60
0.37
0.04
0.27
0.67
0.33
-
-
-
-
-
-
-
-
-
UniAD* [ 29 ]
-
-
-
-
-
-
-
-
0.20
0.42
0.75
0.46
0.02
0.25
0.84
0.37
-
Table 3: End-to-end trajectory planning performance on nuScenes. We evaluate planning quality using L2 displacement error and collision rate across two mainstream protocols: ST-P3 [ 28 ] and UniAD [ 29 ] . * denotes methods using ego-state information. Results for SparseDrive ‡ are re-evaluated following the protocol established by GPT-Driver [ 69 ] .
Method
Detection
Map
Motion
mAP ↑
NDS ↑
AP ped↑
AP divider↑
AP boundary↑
mAP ↑
minADE (m)↓
minFDE (m)↓
UniAD [CVPR23] [ 29 ]
0.380
0.359
–
–
–
–
0.710
1.020
VAD [ICCV23] [ 42 ]
0.276
0.397
0.406
0.515
0.506
0.476
–
–
SparseDrive [ICRA25] [ 86 ]
0.418
0.525
0.499
0.570
0.584
0.551
0.600
0.960
EgoFSD [ICRA26] [ 85 ]
0.410
0.528
0.549
0.557
0.573
0.560
–
–
HiP-AD [ICCV25] [ 88 ]
0.424
0.535
–
–
–
0.571
0.610
–
Table 4: Comparison of perception, mapping, and motion prediction performance on the nuScenes validation dataset.
Table 9
Architecture
Understanding
Perception
Planning
General VQA (%) ↑
DriveBench (%) ↑
Det (NDS) ↑
Map (mAP) ↑
L2 (m) ↓
CR (%) ↓
Shared-Weight Decoder
31.1
50.8
0.437
0.516
0.641
0.175
Mixture-of-Transformers
45.5
54.9
0.439
0.516
0.533
0.140
Table 7: Performance comparison between a shared-weight decoder and Mixture-of-Transformers (MoT) across understanding, perception, and planning tasks. General VQA is averaged over general multimodal benchmarks, DriveBench is used for driving-oriented understanding, and perception and planning metrics are reported on nuScenes.
Model
Params
MMStar ↑
MMMU ↑
RealWorldQA ↑
AI2D ↑
MME ↑
VLMsAreBlind ↑
ChartQA ↑
Qwen2.5-VL [ 4 ]
7B
63.7
51.1
69.0
82.5
2317
40.3
82.5
Qwen3-VL [ 3 ]
8B
63.0
52.8
69.0
83.2
2364
61.9
83.8
InternVL3 [ 122 ]
8B
69.1
54.8
67.8
83.9
2393
42.0
86.6
InternVL3.5 [ 97 ]
8B
66.3
57.3
63.0
82.3
2357
45.4
87.1
GPT-5 Nano [ 83 ]
—
41.3
57.6
60.7
65.7
-
40.2
48.6
UniDriveVLA
8B
43.3
47.3
49.9
76.3
1876
26.6
76.3
Table 8: Comparison of UniDriveVLA with general-purpose and driving-specific models on general multimodal understanding benchmarks.
Vision-Language-Action (VLA) models have emerged as a promising paradigm for end-to-end autonomous driving. However, existing VLAs' training relies heavily on text-centric visual question answering and chain-of-thought reasoning data, which emphasizes linguistic reasoning rather than action-grounded planning. As a result, the learned representations capture semantic knowledge but lack spatial dependencies crucial for reliable trajectory prediction. We propose DriveTeach-VLA, a framework that explicitly teaches VLAs what to see and where to look. Driving-aware Vision Distillation (DVD) injects driving-specific perceptual priors into the vision encoder, while 2D Trajectory-Guided Prompts (2D-TGP) provide spatial conditioning aligned with feasible driving trajectories. Together, they form a vision-guided learning pipeline: what to see (DVD pretraining) - where to look (TGP-guided SFT) - how to act (TGP-guided GRPO). DriveTeach-VLA achieves the state-of-the-art performance on NAVSIM and nuScenes. Our code is available at: https://github.com/ShivaTeam/DriveTeach-VLA.
Yuguang Yang, Canyu Chen, Zhewen Tan +10
School of Electronic Information Engineering, Beihang University · Institute for AI Industry Research (AIR), Tsinghua University · National College for Excellent Engineers, Beihang University +5
Autonomous driving has progressed from modular pipelines toward end-to-end unification, and Vision-Language-Action (VLA) models are a natural extension of this journey beyond Vision-to-Action (VA). In practice, driving VLAs have often trailed VA on planning quality, suggesting that the difficulty is not simply model scale but the interface through which semantic reasoning, temporal context, and continuous control are combined. We argue that this gap reflects how VLA has been built -- as isolated subtask improvements that fail to compose coherent driving capabilities -- rather than what VLA is. We present MindVLA-U1, the first unified streaming VLA architecture for autonomous driving. A unified VLM backbone produces AR language tokens (optional) and flow-matching continuous action trajectories in a single forward pass over one shared representation, preserving the natural output form of each modality. A full streaming design processes the driving video framewise rather than as fixed video-action chunks under costly temporal VLM modeling. Planned trajectories evolve smoothly across frames while a learned streaming memory channel carries temporal context and updates. The unified architecture enables fast/slow systems on dense & sparse MoT backbones via flexible self-attention context management, and exposes a measurable language-control path for action: language-predicted driving intents steers the action diffusion via classifier-free guidance (CFG), turning language-side intent into control signals for continuous action planning. On the long-tail WOD-E2E benchmark, MindVLA-U1 surpasses experienced human drivers for the first time (8.20 RFS vs. 8.13 GT RFS) with 2 diffusion steps, achieves state-of-the-art planning ADEs over prior VA/VLA by large margins, and matches VA latency (16 FPS vs. RAP's 18 FPS at 1B scale) while preserving natural language interfaces for human-vehicle interaction.
Vision-Language-Action (VLA) models have emerged as a promising framework for end-to-end autonomous driving. However, existing VLAs typically rely on sparse action supervision, which underutilizes their powerful scene understanding and reasoning capabilities. Recent attempts to incorporate dense visual supervision via world modeling often overemphasize pixel-level image reconstruction, neglecting semantically meaningful scene representation learning. In this work, we propose LVDrive, a Latent Visual representation enhanced VLA framework for autonomous driving. LVDrive introduces a future scene prediction task into the VLA paradigm, where future representations are learned entirely in a high-level latent space under auxiliary supervision from a pretrained vision backbone. Departing from inefficient autoregressive generation, we jointly model future scene and motion prediction within a unified embedding space, processed in a single forward pass to conduct the future-aware reasoning. We further design a two-stage trajectory decoding strategy that explicitly leverages the learned latent future representations to refine trajectory generation. Extensive experiments on the challenging Bench2Drive benchmark demonstrate that LVDrive achieves significant improvements in closed-loop driving performance, outperforming both action supervised methods and image-reconstruction-based world model approaches.
Xiaodong Mei, Diankun Zhang, Hongwei Xie +3
The Hong Kong University of Science and Technology · Xiaomi EV