Jailbreaking Large Vision-Language Models in Intelligent Transportation SystemsLarge Vision-Language Models (LVLMs) have demonstrated remarkable capabilities in multimodal reasoning and are increasingly deployed in real-world applications, including Intelligent Transportation Systems (ITS). However, these models remain highly vulnerable to jailbreak attacks that circumvent built-in safety mechanisms. This paper presents a systematic security analysis of LVLMs deployed in ITS under carefully crafted jailbreak attacks. We first construct a transportation-specific benchmark of harmful multimodal queries based on OpenAI’s prohibited content categories. We then propose a novel jailbreak attack that combines image typography manipulation with multi-turn prompting to conceal malicious intent while steering the model toward unsafe responses. To mitigate these attacks, we introduce a multi-layered response filtering defense that integrates rule-based filtering with a zero-shot classifier. Extensive experiments on both open-source and commercial LVLMs demonstrate the effectiveness of the proposed attack and defense. Attack success is evaluated using GPT-4-based toxicity assessment together with manual verification, and comparisons with existing jailbreak techniques highlight the significant security risks posed by image typography manipulation and multi-turn prompting in LVLM-enabled intelligent transportation applications.