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Citation |
Zwahlen HT, Devi Vel U. Transp. Res. Rec. 1994; 1456: 125-138. |
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Copyright |
(Copyright © 1994, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing) |
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DOI |
unavailable |
PMID |
unavailable |
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Abstract |
A daytime field study was conducted to determine the conspicuity in terms of peripheral visual detection and recognition of different fluorescent and nonfluorescent color targets against different backgrounds. Ten color targets [6 x 12 in. (15 x 30 cm)], of which six were nonfluorescent and four were fluorescent, were tested against different nonuniform multicolored backgrounds. Three different painted plywood boards of 4 x 4 ft (1.2 x 1.2 m) depicting either typical city, fall foliage, or spring foliage background colors were used as the backgrounds. The stimuli (color targets) were presented at three different peripheral angles (20, 30, and 40 degrees to the right of the line of sight) against the different backgrounds. Twelve subjects with normal color vision between the ages of 20 and 22 years participated in the experiment, which was conducted on an unused airport runway. A randomized block experimental design was used in such a way that for each subject the order of presentation of the three peripheral angles was random so that each angle occurred exactly once. Furthermore, for a given angle the order of presentation for the backgrounds was randomized so that each background occurred exactly once. For each background and for each of the two blocks of 10 colors each color was randomized in such a way that each color target appeared exactly once in the first block as Replication 1 and exactly once in the second block as Replication 2. Daytime chromaticity measurements were recorded for all of the color targets and background colors along with daytime luminance measurements of all of the color targets and backgrounds. The data were analyzed for two conditions: (a) detection percentage of total responses on the basis of the total number of presentations in which the subject detected the presence of a color target but in which the subject's color recognition response could be either the correct color or an incorrect color and (b) recognition percentage of the correct color target recognitions on the basis of the total number of presentations in which a subject's response with regard to the recognition of the color of the target was correct. In general, fluorescent yellow was found to be best detected and fluorescent orange was found to be best recognized against any of the three backgrounds investigated. Looking at the results of the study and the increased detection and recognition performances achieved with fluorescent colors for the conditions investigated, one may tentatively conclude that the fluorescent colors investigated in the study are considerably more conspicuous during daytime in terms of the peripheral detection and recognition percentages. It is recommended that designers of traffic signs, personal conspicuity enhancement items and devices, and roadside traffic control devices consider the superior visual conspicuity properties of fluorescent colors (especially fluorescent yellow and fluorescent orange) and incorporate them in designs when the highest possible daytime target conspicuity is absolutely necessary. Language: en |