Vehicle beacons : conspicuity and subjective evaluation as a function of colour and type.

In some field studies, red, yellow, light blue, and dark blue rotating and flashing beacons have been compared mainly from peripheral conspicuity point of view. But also some subjective evaluations have been made. The results show that from purely visual point of view the yellow beacon is superior. The red beacon is inferior in nighttime conditions but good under bright daylight conditions which seem to be the worst from safety point of view. The blue beacons are almost too good in nighttime conditions in the respect that they cause discomfort but they are poorly visible in bright daylight conditions. A light blue beacon is more conspicuous than a dark blue beacon. Flashing light blue beacons are equally conspicuous to rotating light blue beacons but cause more discomfort.