Rethinking Language’s Role in Efficient VLA for Autonomous Vehicles: Toward Smarter, Trustworthy Driving

Tongfei Guo, Lili Su


Abstract
Vision-Language-Action (VLA) models are reshaping autonomous driving (AD) by unifying perception, reasoning, and control through language, enabling semantic grounding, interpretable decisions, and better long-tail generalization. But language is expensive onboard: latency and memory budgets are tight, and autoregressive decoding is inherently sequential. This work reframes the central question as when and where language should act at inference, since inference cost recurs at every deployed frame while training cost is paid once. We introduce the Language Residue taxonomy to organize methods by their inference-time use of language: train-time-only supervision (L1), latent non-textual reasoning (L2), conditional invocation (L3), and full per-frame generation (L4). We review representative methods and tag each across five deployment axes (latency, parameters, memory, FLOPs, tokens), analyzing them on major open- and closed-loop driving benchmarks (e.g., nuScenes, NAVSIM, Bench2Drive). We further trace how efficient methods from NLP/LLM are adapted in AD, identifying the constraints and motivations driving these adaptations. A continuously updated repository will be available at Github.
Anthology ID:
2026.emnlp-main.2504
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
56933–56947
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URL:
https://aclanthology.org/2026.emnlp-main.2504/
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Cite (ACL):
Tongfei Guo and Lili Su. 2026. Rethinking Language’s Role in Efficient VLA for Autonomous Vehicles: Toward Smarter, Trustworthy Driving. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 56933–56947, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Rethinking Language’s Role in Efficient VLA for Autonomous Vehicles: Toward Smarter, Trustworthy Driving (Guo & Su, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2504.pdf