COLOR APPEARANCE OF TRAFFIC CONTROL DEVICES UNDER DIFFERENT ILLUMINANTS

Color has traditionally been used to code safety information because of its ability to attract attention and evoke a rapid response. Research on color coding, highway safety color codes, conspicuity, illuminant color shifts, and retroreflective materials has been reviewed to evaluate the effectiveness of the current chromaticity specifications for highway signs and markings. These current specifications require colors of medium lightness and saturation (except yellow), and sometimes can appear quite dark. Data from a previous study were analyzed to compare color appearance data (color name, lightness, and saturation) under seven different illuminants for a set of American National Standards Institute (ANSI) and highway colors. This analysis demonstrated that the ANSI colors, particularly safety yellow, were identified more accurately in terms of color name, lightness, saturation, and primary hue than was the corresponding highway color. A shift toward ANSI safety yellow from highway yellow is suggested.