LUMINANCE REQUIREMENTS FOR SIGNS WITH COMPLEX BACKGROUNDS.

This article describes a research study establishing luminance requirements to ensure that a yellow diamond warning sign is conspicuous at night. The study developed a procedure for rating sign locations to identify those locations requiring higher luminance level signs. The article presents this procedure, the study's major conclusions, and recommendations on the maximum allowable sign luminance deterioration that can still provide the driver with adequate detection distances. The significance of this study is that it attempts to provide standards for signing luminance by developing criteria based on the complexity of the surrounding visual environment.