How do design factors of stacked directional signs affect their visual cognition?

Stacked directional signs are widely used on Chinese roads, but research on them is relatively scarce. This study aimed to investigate the effects of the Language used, Layout format, Amount of information, and use of Separating lines on the visual cognition of stacked directional signs. A visual cognition experiment involving thirty-two drivers was conducted, and the reaction time and response accuracy were recorded. The results revealed that a greater Amount of information was correlated with increased visual cognition reaction times. Bilingual signs exhibited significantly greater reaction times compared to monolingual counterparts, while a simpler Layout format resulted in shorter reaction times. The Language used, Amount of information, Layout format, and use of Separating lines were in decreasing order of importance for visual cognition reaction time, with a high Amount of information having the greatest effect. The implications of these findings can be applied to the design and optimisation of stacked directional signs.