An Evaluation of the Flash Pattern of LED Warning Lights for Improving Distinctness A Shiraiwa1, E Aiba1, T Shimotomai2, H Mazaki3, S Uekawa3, N Nagata1, Y Kitamura3 |
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1Research Center for Kansei Value Creation, Kwansei Gakuin University / AIST / JSPS, Japan |
| In recent years, the number of emergency vehicles equipped with light-emitting diode (LED) warning lights has increased. The purpose of this study is to investigate the optimal flash patterns of LED warning lights and to improve the visibility of emergency vehicles. We are able to control flash patterns of LED lights via computer. We used various flash patterns with a combination of lighting time (ON time 11, 22, 33, 44, 55, 66, 99, and 132 msec) and no-lighting time (OFF time 11, 22, 33, 44, 55, 66, 99, and 132 msec), and measured the reaction time (i.e. ‘distinctness’) of LED warning lights under the conditions of varying ages (a young group and an old group), intensity of illumination against a background (bright 330 lux, or dark 28 lux), and luminance of LED warning lights (bright 220 cd/m2, or dark 26 cd/m2) by psychological experiments. We found that (1) OFF time affected the reaction time (distinctness), (2) the flash pattern of 33-msec OFF time provided optimal visibility regardless of ambient conditions in any brightness, and (3) reaction time was not affected by age. |
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