2008 Volume 9 Issue 1 Pages 59-66
The present study is part of a design proposal for signposts on the Tokyo Metropolitan expressway. Legibility and recognizability of candidate fonts of full-scale signposts were measured. The fonts used were Shin Go M and VialogLT M. Thirty-two participants read Japanese, alphabetic and alphanumeric nonsense syllables whose sizes changed in 5 steps; for Japanese syllables, 500, 450, 400, 350, and 300 mm, for alphabetic and alphanumeric syllables, 400, 350, 300, 250 and 200 mm. Two types of distance were measured. For legibility, the participants had to stop when they thought they could read the word. For recognizability, they had to stop when they could certainly read the word. The legibility distance was longer than recognizability one. Although these distances became longer according to letter size, there was no significant difference between 500 mm Japanese letters and 450 mm ones. The alphabetic words were easier to read than Japanese ones and alphanumeric ones. It was suggested that to get the same visibility the letter height of the alphabet was around 70 % of the Japanese letters. Some methodological issues in the experiment concerning design practices were also discussed.
