Effects of text space of Chinese-English bilingual traffic sign on driver reading performance

Chinese-English bilingual traffic signs (CEBTS) are widely applied in public spaces within China, but few studies have addressed the spatial arrangement of the two languages on CEBTS and road standards provide little guidance for it. This study investigates whether changes in ‘separating space’, the vertical space between bilingual place names on CEBTS, affects driver reading performance. Ten sign combinations were developed using variations in the sign’s graphic complexity, total number of place names, and the spatial distribution of the place names. Each sign was displayed in a 3D graphics rendered clip of someone driving towards the road sign in random order. Participants identified destinations by reading the signs shown in the clip. The speed and the accuracy of responses was recorded. 39 English-reader participants were recruited and equally split into three groups. Three levels of separating space 0.5H, 0.75H and 1H; H refers to one Chinese character height, were prepared according to a between-subject factorial design. The results show that the separating space affected the response time regardless of sign combinations. Both 0.5H and 0.75H separations caused significant faster reading time and higher accuracy than 1H, but 0.75H appears to achieve better result. The findings contribute to the legibility research concerning bilingual signs with two very different character sets. This study considers improving sign legibility through spatial arrangement of the bilingual text, which is currently limited in the field of Chinese road sign legibility. The findings could inform future standards for Chinese-English road signs.