Recognition of traffic signals viewed through colored filters

Experiments were carried out to provide an empirical basis for setting color standards for sunglasses. Nineteen individuals, ten with anomalous color vision, viewed traffic signals through a series of color filters. Limits on the apparent color shift for the amber and green signals as well as for D65 are presented on a 1931 CIE chromaticity diagram. Limits on the reduction in the apparent luminosity for each of the three signals are given in terms of the minimum transmittance of the lens for each signal.