DETERMINING DAYLIGHTING PARAMETERS BY A LUMINANCE MAPPING SYSTEM AND SCALE MODELS

This paper provides a synthesis of the human factors and visual scienc e literature related to the visibility and conspicuity of traffic sign als. Based on this synthesis the author has developed a prioritized li st of research required to address some of the more important issues r elated to the visibility and conspicuity of traffic signals. Visibilit y is defined by the probability of detection for an average observer u nder favorable conditions, while conspicuity is that property that all ows a signal to stand out with respect to other similar but irrelevant signals under all possible visual conditions and for all types of obs ervers. The following areas of traffic signal research have been synth esized: color; daytime intensity and its distribution; nighttime inten sity; limits of phantom; and the effects of backplates, depreciation, driver characteristics, and environmental characteristics on daytime a nd nighttime intensity and on distribution of intensity. Some of the h igher priority research includes the effect of depreciation on intensi ty, development of standards for symbolic signals, development of stan dards for newer devices such as LEDs and fiberoptics, specification of maximum allowable nighttime intensities, evaluation of the effect of background complexity on intensity and distribution, and intensity req uirements for color-deficient drivers.