Measurement of Traffic Signal Colors

Abstract

Traffic signal colors have been measured by a physical color measurement method and a appraisal color naming method for comparison of the both methods. Angles subtended between the visual line and a traffic signal lamp axis were changed to make color variation. For reference color chips were also measured. Four subjects were used in the appraisal experiment. As a results, it is clarified that appraisal color naming method has a good correlation with the physical color measurement method. Further, It is assumed that subjects decided the hue of a signal lamp to depend on the color of brighter and center part of the lamp surface. Moreover, effect of lamp voltage variation was measured. And difference between the chromaticities measured in a dark room and outdoor, were presented.