Conspicuity of high visibility clothing

Status:

completed 06/2013

Aims:

Studies on retro-reflective safety garments repeatedly revealed increased conspicuity of vulnerable road users. However, most evidences were obtained employing subjects who knew which targets they had to look for, whereas in real traffic drivers usually don't know where or when critical situations will occur. In order to avoid an instruction bias gaze behavior of persons who were naive regarding the objective of the study was analyzed.

Activities/Methods:

Twenty-seven subjects aged 20-73 years encountered six different garments in three locations: urban, residential, and rural unlit road. For setting the baseline completely black apparel was used. The other garments were a long sleeve sweatshirt with retro-reflective motif at the chest, a cycling jacket with contour stripes at arms and torso, an area-reflective vest, a yellow-fluorescent worker vest according to DIN EN 471, and an identical vest without retro-reflective stripes. All subjects completed a second run in which they were instructed to indicate all pedestrians they recognized. Thus, it was possible to compare detection to recognition of the targets. Some of the trials were carried out during rain in order to increase the study’s relevancy to practice.

Results:

Only Garments with larger reflective areas, namely the jacket with contour stripes, the DIN EN 471 vest, and the area-reflective vest significantly improved conspicuity. The smaller reflective motif and the merely fluorescent vest did not perform better than pure black clothing. Furthermore even the larger reflective areas or fluorescence had only limited statistical impact on the recognition of a pedestrian while the reflective motif was at the level of black clothing. All differences found between the garments are due to encounters in unlit road sections. Neither detection nor recognition was substantially increased by retro-reflectors in lit areas. Unexpectedly, rainfall did not impair the effect of retro-reflection but this finding remains not sufficiently substantiated due to a very small subsample size. The aforementioned results on smaller reflectors raise concerns that especially users of correspondently equipped casual clothes could fall prey on a delusive feeling of safety. Although retro-reflectors revealed no significant advantages in lit regions it cannot be inferred that they are not useful in built-up areas. Even a small decline in illumination along the way can make them reasonable. After all, the question arises how retro-reflectors can not only improve detection but also recognition of pedestrians. Further research on appropriate configurations is needed.

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