Perceived ability and influencing factors of the signage system for color vision deficiency groups: A case study of metro travel process

Abstract

Introduction

Color plays a crucial role in wayfinding signage, enhancing information filtering and reception. However, individuals with color vision deficiency (CVD) struggle to interpret color-coded information, impeding navigation and daily mobility. With the rapid development of urban rail transit in China, metro systems rely heavily on color-coded signage, exacerbating challenges for CVD individuals. Existing research focuses mainly on digital interfaces, with limited attention to how CVD groups perceive signage in complex environments, highlighting the need for studies addressing their wayfinding difficulties.

Methods

This study examines the metro transit process at Lücuo Station in Xiamen, selecting two critical spatial nodes in urban streets and two within the station. Utilizing eye-tracking technology, 360° panoramic imaging, and CVD simulation techniques, the research considers daytime versus nighttime conditions and normal color vision (NCV) versus CVD. A total of 94 participants were recruited, yielding 88 valid datasets. Four eye-tracking experiments were conducted, employing variance and correlation analysis to compare visual metrics. The study explores signage perception across complex environments and examines how color contrast affects visibility and readability under varying conditions.

Results

Experimental results indicate that at certain experimental nodes, simulated CVD participants were approximately 30 % slower in noticing existing signage and 50 % slower in decision-making compared to participants with NCV. However, in environments with complex color schemes, simulated CVD participants demonstrated superior performance, detecting existing signage 40–55 % faster than their NCV counterparts, showing resistance to interference from visually rich color environments. Furthermore, variations in outdoor lighting conditions significantly impacted participants' signage perception abilities by affecting the contrast between signage and environment.

Conclusions

This study explores subway signage perception by CVD users, highlighting challenges with non-color-friendly designs and poor nighttime lighting. CVD users filter distractions better in complex visuals but struggle with low contrast. This research advocates inclusive urban design, offering a foundation for future accessibility improvements.