Organizations: School of Vehicle and Mobility, Tsinghua University · Suzhou Automotive Research Institute, Tsinghua University · State Key Laboratory of Intelligent Vehicle and Mobility, Tsinghua University
Vehicle-to-Everything (V2X) cooperation enables beyond-line-of-sight perception, mitigating occlusions in single-vehicle sensing. However, existing V2X benchmarks provide limited support for closed-loop evaluation and language-grounded supervision, hindering the development of vision-language models (VLMs) for end-to-end cooperative driving. To address these limitations, we introduce V2XBench, a simulation platform featuring synchronized ego--roadside sensing and closed-loop evaluation, together with Chat-V2XBench, a progressively structured VQA dataset for cooperative reasoning. Building upon this benchmark infrastructure, we propose AURORA, an end-to-end cooperative driving framework. Equipped with a dual-view perception architecture, AURORA mitigates spatial and semantic discrepancies across ego and roadside viewpoints through a query-level Cross-View Query Alignment and Fusion (CQAF) module. Leveraging the resulting unified tokens, a LoRA-adapted VLM bridges semantic reasoning and generative trajectory planning. Extensive closed-loop evaluations on V2XBench demonstrate that AURORA achieves state-of-the-art performance in heavily occluded scenarios, with a Route Completion rate of 98.21% and a Driving Score of 76.02, while requiring low roadside communication bandwidth. Ultimately, this work pioneers an extensible V2X--VLM paradigm, paving the way for next-generation cooperative autonomous driving.
Figures & tables
Benchmark
Year
Real/ Sim.
View
Scenario Types
Closed- Loop
E2E- Sim
With Traffic Light
With VRUs
With VQA
nuPlan
2021
Real
Single-vehicle
73
✓
×
✓
✓
×
nuScenes
2019
Real
Single-vehicle
-
×
×
×
✓
×
CARLA LB V2
2023
Sim.
Single-vehicle
21
✓
✓
✓
✓
×
Bench2Drive
2024
Sim.
Single-vehicle
44
✓
✓
✓
✓
×
WIBAM
2021
Real
Infrastructure
1
×
×
✓
×
×
V2X-Sim 2.0
2022
Sim.
V2X
-
×
×
×
×
×
Table 1: Comparison with representative public autonomous driving and V2X datasets. V2XBench is the only V2X benchmark to evaluate closed-loop E2E simulation with VQA capabilities.
Figure 1: Platform overview of V2XBench. V2XBench integrates route-adaptive roadside infrastructure, synchronized ego–RSU sensing, offline multi-agent data generation, Chat-V2XBench VQA construction, and online closed-loop cooperative driving evaluation within a unified CARLA-based simulation platform.
Figure 2: The pipeline of our AURORA, a holistic end-to-end framework for V2X cooperative driving. The architecture first utilizes dual-view perception to encode synchronized ego and roadside streams into spatial queries and semantic tokens. Roadside detection and map queries are transmitted and fused in the ego frame by the Cross-View Query Alignment and Fusion (CQAF) module, while ego semantic tokens are refined via query-conditioned cross-attention. The resulting fused tokens ground a VLM-guided generative planner that bridges semantic reasoning and action to roll out future trajectories conditioned on a dedicated waypoint token.
Method
Reference
Modality
Avg. mAP ↑
NDS ↑
Main-class mAP ↑
Trans. Cost (BPS) ↓
Vehicle
VRUs
Traffic Light
Traffic Sign
No Fusion
–
Camera
0.478
0.497
0.513
0.532
0.204
0.301
–
V2X-ViT
ECCV 22
LiDAR
0.350
0.485
0.521
0.042
0.530
0.397
2.10×108
CoDriving
IEEE TPAMI 25
LiDAR
0.393
0.343
0.528
0.627
0.019
0.161
1.24×108
UniV2X
AAAI 25
Camera
0.271
0.382
0.305
0.383
0.131
0.247
1.09×106
UniMM-V2X
AAAI 26
Camera
0.338
0.466
0.396
0.499
0.056
0.178
1.09×106
Table 2: Cooperative 3D detection results on the V2XBench test split. All methods are trained and evaluated under the same ego–roadside cooperative setting. For clarity, we report class-wise mAP only for the main categories. BPS denotes bytes per second (B/s) for the roadside transmission cost.
Method
Reference
Modality
Closed-loop Metric
Open-loop Metric
Trans. Cost (BPS) ↓
DS ↑
RC ↑
Efficiency ↑
Comfortness ↑
Avg. L2 (m) ↓
No Fusion
–
Camera
52.09
93.84
15.82
126.12
1.63
–
CoDriving
IEEE TPAMI 25
LiDAR
56.75
91.23
18.59
193.55
1.38
1.24×108
UniV2X
AAAI 25
Camera
33.76
86.76
13.1
128.82
2.19
4.05×106
UniMM-V2X
AAAI 26
Camera
49.26
87.33
5.2
74.55
1.03
4.66×106
AURORA (Ours)
–
Camera
76.02
98.21
16.60
124.54
1.60
4.84×106
Table 3: Planning results on the V2XBench test split under both closed-loop and open-loop evaluation. DS and RC denote Driving Score and Route Completion, respectively. BPS denotes bytes per second (B/s) for the roadside transmission cost.
Setting
Perception
Closed-loop
Open-loop
mAP ↑
NDS ↑
DS ↑
RC ↑
Avg. L2 (m) ↓
w/o Fusion
0.478
0.497
52.09
93.84
1.63
w/ Fusion (Ours)
0.548
0.568
76.02
98.21
1.60
Table 4: Ablation on ego–roadside fusion. DS and RC denote Driving Score and Route Completion. “w/” and “w/o” denote with and without.
Planner
Closed-loop
Open-loop
DS ↑
RC ↑
Avg. L2 (m) ↓
Avg. Col. (%) ↓
MLP
56.98
88.38
1.94
5.18
Diffusion
66.21
92.61
1.73
3.91
VAE (Ours)
76.02
98.21
1.60
3.47
Table 5: Ablation on generative planners. DS and RC denote Driving Score and Route Completion.
Setting
Closed-loop
Open-loop
DS ↑
RC ↑
Avg. L2 (m) ↓
Avg. Col. (%) ↓
w/o VQA
67.98
92.11
1.54
3.57
w/ VQA (Ours)
76.02
98.21
1.60
3.47
Table 6: Ablation on VQA supervision. DS and RC denote Driving Score and Route Completion. “w/” and “w/o” denote with and without.
Appendix figures & tables6 assets
Supplementary material from the paper’s appendix.
Appendix
Sensor
Configuration
Mounting
Ego vehicle
6× RGB cam.
1024×512 , FOV 110∘
surround, z=1.8 m
6× Depth cam.
1024×512 , FOV 110∘
paired with RGB
6× Sem. cam.
1024×512 , FOV 110∘
paired with RGB
1× LiDAR
10 Hz, 0.6 M pts/s
roof, z=2.5 m
BEV semantics
rasterized GT map
—
Appendix
Table 7: Sensor suite of the ego vehicle and each roadside unit (RSU) in V2XBench. All cameras additionally provide spatially aligned depth and (for the ego) semantic-segmentation streams.
Table 8: The 38 safety-critical scenario types in V2XBench, grouped into V2X scenarios (occlusion- and beyond-line-of-sight-dominated, where roadside infrastructure is most beneficial) and other challenging autonomous-driving scenarios.
Figure 3: Representative visualizations of synchronized V2XBench sensory data, including RGB images, spatially aligned depth maps, and LiDAR point clouds captured from ego and roadside views.
Figure 4: The Chat-V2XBench question bank. Each keyframe is annotated with questions drawn from the four levels of the progressive reasoning hierarchy.
Figure 5: The prompt used to auto-label the open-ended QA pairs with Qwen3-VL-Plus, conditioning the model on the multi-view imagery and the ground-truth object hints.
Stage
Batch Size
Epochs
Base LR
Freeze Backbone
Stage 1
12
4
5×10−5
False
Stage 2
12
4
5×10−5
False
Stage 3
8
4
4×10−5
False
Stage 4
8
6
8×10−5
True
Stage 5
6
4
8×10−5
True
Appendix
Table 9: Stage-wise training hyperparameters for the submitted AURORA checkpoint. Shared optimizer and schedule settings are described in the text.
Single-vehicle Vision-Language Models (VLMs) are fundamentally constrained by sensor occlusions. While Vehicle-to-Everything (V2X) systems mitigate this, current benchmarks lack the cooperative reasoning required for resolving ambiguities in complex environments. We introduce D2-V2X, a spatially-aware Question-Rationale-Answer (QRA) benchmark featuring 8,500 triplets derived from multimodal vehicle and infrastructure sensors. We additionally establish a baseline that aligns 3D LiDAR features with the VLM's latent space. By enforcing natural language Chain-of-Thought rationales prior to structured JSON outputs, our model is forced to explicitly articulate spatial relations. Our experiments demonstrate that grounding VLMs in cooperative LiDAR achieves 24.4% recall in identifying occluded hazards compared to near-zero in zero-shot models and reduces spatial estimation error for visible objects by 77% compared to the zero-shot baseline. While the model achieves a functional decision-making F1-score of 53.5, we identify 3D-to-2D projection as a fundamental bottleneck in current VLM architectures, establishing a new baseline for future innovation. Data, code, and trained models available at https://github.com/KevinRichard1/D2-V2X
Vision-Language-Action (VLA) models have recently achieved impressive performance for end-to-end autonomous driving, yet existing approaches are primarily designed for an individual single autonomous driving agent with limited support for cooperative perception, reasoning, and planning. We present Cooperative Multi-agent Unified Driving with Reasoning (CMU-Drive), a closed-loop end-to-end benchmark for evaluating cooperative autonomous driving with multiple connected autonomous vehicles (CAVs) operating in safety-critical driving scenarios with background traffic participants. We further propose Vehicle-to-Vehicle Vision-Language-Action (V2V-VLA), a cooperative VLA model that integrates cooperative driving into a single forward pass by jointly generating driving actions, future waypoints, language reasoning, and communication policies. Experiments on CMU-Drive establish the first benchmark and baseline for cooperative VLA driving and provide a foundation for future research on multi-agent, closed-loop, end-to-end cooperative autonomous driving. Our code, benchmark, and model checkpoint will be publicly released to facilitate open-source research.
We present OmniV2X, a generative foundation model for vehicle-to-everything (V2X) cooperative driving. The model directly interprets independent context sequences comprising multi-modal and multi-agent observations. The new design mitigates the computational cost of dense 3D perception, the vulnerability to data scarcity in cooperative scenarios, and the poor compliance with standardized messaging in existing methods that fuse multi-modal inputs into a shared representation. For training, we present an end-to-end supervised pipeline using a downstream trajectory generation loss, in which a high-capacity generative sequence planner implicitly learns to steer the model and leverage multi-modal inputs via cross-attention injection. As a foundation model, we demonstrate that OmniV2X pre-trained on large-scale single-agent planning datasets can efficiently adapt to cooperative environments by integrating the conditioning context with lightweight, standard-compliant V2X tokens. Evaluated on the DAIR-V2X-Seq dataset, OmniV2X outperforms existing end-to-end cooperative driving baselines, achieving state-of-the-art performance with less than 10% of the fine-tune V2X dataset and less than 1% of the communication bandwidth. We conduct comprehensive evaluations to demonstrate its computational efficiency and robustness under real-world constraints.
Juntong Peng, Juanwu Lu, Yupeng Zhou +3
College of Engineering, Purdue University, West Lafayette, IN 47907, USA