Investigating the optimal scale for subway station hall designs based on psychological perceptions and eye-tracking methods

With the rapid development of underground rail transit, subway spaces have become an essential part of modern urban life. While carefully designed subway spaces with appropriate scales can significantly enhance passengers' spatial perception and associated visual comfort, there has been a lack of quantitative approaches to systematically investigating the optimal scale for subway station hall (SSH) designs. In this study, we identified five common spatial morphology types of SSH from cross-sections: column-free rectangular, column-free curved, column-free vertical-wall and curved-ceiling, single-column rectangular, and double-column rectangular SSH. We then constructed representative models with different spatial scales under fixed viewpoints as experimental stimulus images from each spatial type of SSH, generating 84 scenes in total. The semantic differential (SD) method, eye-tracking technology, and associated statistical analyses were employed to investigate the relationships between participants' psychological perceptions and the spatial scale of SSH. The results indicate that the width-to-height ratio (D/H), total fixation time and the number of fixations in areas of interest (AOI) are key factors affecting passengers’ visual comfort in SSH. While the column-free rectangular SSH was preferred by participants, better scenes that are more visually pleasing as well as optimal spatial scale ranges were also identified in each spatial type of SSH. This study provides strong evidence-based support for the design and optimization of subway stations through both subjective and objective methods.