THE VISIBILITY OF ALPHABETIC AND SYMBOLIC TRAFFIC SIGNS
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. The experiments show that: (a) the average 50 percent threshold legibility distance for symbolic signs is about twice that for alphabetic signs for all levels of visual acuity; (b) the shape coding included on the signs does not enhance their legibility among a set of signs; (c) the sign size required for 0.95 probability of correct identification is approximately 1.7 times larger than the size giving 0.50 probability of correct identification; and (d) reduced visual acuity has a predictable effect on legibility distance, e.g. a change in visual acuity from 6/6 to 6/12 halves the 50 percent threshold legibility distance. Practical sign design for the actual driver population is discussed and, it is concluded that the use of symbolic sign messages and larger alphabetic sign messages is required.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/00050164
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Corporate Authors:
ARRB
Melbourne, Victoria Australia -
Authors:
- Jacobs, R J
- Johnston, A W
- Cole, B L
- Publication Date: 1975-5
Media Info
- Pagination: p. 68-86
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Serial:
- Australian Road Research
- Volume: 5
- Issue Number: 7
- Publisher: ARRB
- ISSN: 0005-0164
Subject/Index Terms
- TRT Terms: Design; Legibility; Symbols; Traffic signs; Visibility; Visual perception
- Uncontrolled Terms: Reduced visibility
- Old TRIS Terms: Traffic sign design
- Subject Areas: Design; Highways; Operations and Traffic Management; Safety and Human Factors;
Filing Info
- Accession Number: 00133530
- Record Type: Publication
- Source Agency: Highway Safety Research Institute
- Files: TRIS, ATRI
- Created Date: Aug 23 1976 12:00AM