V-RoAst: Visual Road Assessment. Can VLM be a Road Safety Assessor Using the iRAP Standard?

원문 초록

Road traffic crashes result in millions of deaths annually and significant economic burdens, particularly on Low- and Middle-Income Countries (LMICs). Road safety assessments traditionally rely on human-labelled data, which is labour-intensive and time-consuming. While Convolutional Neural Networks (CNNs) have advanced automated road safety assessments, they typically demand large labelled datasets and often require fine-tuning for each new geographic context. This study explores whether Vision Language Models (VLMs) with zero-shot capability can overcome these limitations to serve as effective road safety assessors using the International Road Assessment Programme (iRAP) standard. Our approach, V-RoAst (Visual question answering for Road Assessment), leverages advanced VLMs, such as Gemini-1.5-flash and GPT-4o-mini, to analyse road safety attributes without requiring any labelled training data. By optimising prompt engineering and utilising crowdsourced imagery from Mapillary, V-RoAst provides a scalable, cost-effective, and automated solution for global road safety assessments. Preliminary results show that while VLMs achieve lower performance than CNN-based models, they are capable of Visual Question Answering (VQA) and show potential in predicting star ratings from crowdsourced imagery. However, their performance is poor when key visual features are absent in the imagery, emphasising the need for human labelling to address these gaps. Advancements in VLMs, alongside in-context learning such as chain-of-thought and few-shot learning, and parameter-efficient fine-tuning, present opportunities for improvement, making VLMs promising tools for road assessment tasks. Designed for resource-constrained stakeholders, this framework holds the potential to save lives and reduce economic burdens worldwide. Code and dataset are available at: https://github.com/PongNJ/V-RoAst.