00335158

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http://onlinepubs.trb.org...trcircular/229/229-004.pdf

The data presented clearly indicate that retroreflective treatments on pedestrians can increase the distance at which they are detected and recognized. Thus, it is a reasonable extension of these results to postulate a safety benefit from the widespread use of appropriately designed retroreflective garments at night. However, it must be remembered that all subjects in the reported experiments were alerted, had normal vision and were neither fatigued nor intoxicated when the data were collected. Therefore, care must be exercised in extending these findings, particularly the extent of improvement in detection and recognition, to the entire population of drivers. Until additional research can be conducted to refine even further the optimal design for a retroreflective countermeasure for pedestrians, the foregoing findings can be utilized to begin to enumerate several basic principles. First, to improve detection, one should use bright target materials. Consistently, these studies showed that each increment in target brightness tested produced a corresponding increase in detection distance. In these studies, brightness was a more important influence on detection than was the total target area, even though the targets ranged in size from a minimum of four square inches to a maximum of several square feet. Second, identification of the targets as pedestrians requires more than mere early detection. Anthropomorphism of the target shape greatly aids recognition. In these studies, shapes which are commonly associated with "people" led to effective identification even though the shapes only partly reproduced the human form. Retroreflective jackets seemed to produce a significant improvement in recognition. Retroreflective trousers were significantly better than jackets, and the combination of the two was better than either alone. Shapes which did not represent human figures, articles of clothing or other visual forms associated with the human figure--spots and stripes--did not enhance and may actually inhibit recognition of the pedestrian figures. Hence, for improved safety, it would appear best to outline the body as completely as possible with the brightest material available. Finally, the excellent prediction of suburban course results from dark course findings is of interest. It means that the relative effectiveness of new pedestrian conspicuity enhancers can be assessed under totally dark field test conditions, which are easier to establish and control for experimental purposes. Thus, the further refinement of the design of retroreflective treatments for pedestrians should not be significantly hampered by test and evaluation costs. (Author)

Presented at the Symposium on Conspicuity on the Highway, St. Paul, Minnesota, 24-26 June 1980. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

HS-032 447

p. 17-21

1981-5

Transportation Research Circular

Figures (6) ; References (8)

Brightness; Clothing; Detection and identification; Detectors; Night visibility; Pedestrian safety; Retroreflectors

Highways; Safety and Human Factors; I83: Accidents and the Human Factor

HSL, TRIS, TRB

Oct 28 1981 12:00AM