Legibility and readability of light reflecting matrix variable message road signs

Collins, J.J. and Hall, R.D. (1994) Legibility and readability of light reflecting matrix variable message road signs. Lighting Research and Technology, 24, (3), 143-148. (doi:10.1177/096032719202400304).


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Driving is a dynamic task. Hence, for a given message, readability depends on legibility distance and reading time. In laboratory simulation and outdoor tests, the variables of pixel shape, letter width/height ratio, font and letter separation were studied. Nearly 100 subjects took part in the laboratory simulation using monochrome slides. Half the subjects assessed legibility distance while the remainder determined reading time. The method of limits was used to determine the thresholds for legibility distance and reading time for nearly 50 different formats of matrix sign. For legibility distance, the thresholds found in the laboratory were validated using real signs in an outdoor situation. However, it was not possible to validate reading times in a similar manner due to lack of availability of sufficiently large full scale signs. Variations in format had a marked effect on legibility distance, but a lesser impact on reading time. In general, letters with any regular shaped pixel, a width/height ratio approaching 1.0, an upper case font and a letter separation of two pixels were found to be most effective.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1177/096032719202400304
ISSNs: 1365-7828 (print)
1477-0938 (electronic)
Related URLs:
Subjects: H Social Sciences > HE Transportation and Communications
Divisions: University Structure - Pre August 2011 > School of Civil Engineering and the Environment
ePrint ID: 189077
Date :
Date Event
Date Deposited: 21 Jun 2011 13:59
Last Modified: 31 Mar 2016 13:40
URI: http://eprints.soton.ac.uk/id/eprint/189077

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