Citation

Jacobs RJ, Johnston AW, Cole BL. Aust. Road Res. 1975; 5(7): 68-86.

Copyright

(Copyright © 1975, Australian Road Research Board ARRB)

DOI

unavailable

PMID

unavailable

Abstract

The techniques used in this study permit the determination of sign visibility under controlled conditions for observers with both normal and reduced visual acuity. Sixteen familiar road sign messages (regulatory and warning) were examined in both alphabetic and symbolic form for observers with visual acuities from normal to as low as 6/21. Threshold legibility distances were calculated using probit analysis for individual signs and groups of signs. Among the conclusions reached are that the average 50 per cent threshold legibility distance for symbolic signs is about twice that for alphabetic signs for all levels of visual acuity, and that the shape coding included on the signs does not enhance their legibility among a set of signs. Practical sign design for the actual driver population is discussed and it is concluded that the use of symbolic sign meassges and larger alphabetic sign messages is required.

Language: en