Two independent studies were conducted to determine the distances at which the color and the outside shape of reflectorized targets were recognized at night under automobile low-beam illumination. Thetargets were flat plates presented in one of three outside shapes and covered with retroreflective sheeting using one of six colors. All flat plates were prepared in such a way that they had the same area and close to the same specific intensity per unit area. In study 1, the color recognition distances and the shape recognition distances were determined. In study 2, the only color recognition distances investigated were for square targets that had the same area and specific intensity per unit area as used in study 1. Summary measures for recognition distances and confusion matrices were obtained to examine the effects of color and shape. The results of study 1 indicate that the recognition distances for highly saturated colors are abouttwice the recognition distances for outside shapes. The statisticalanalysis results of both studies show that the recognition distances for highly saturated colors are significantly different and that some colors have longer recognition distances than others. In addition, on the basis of a statistical analysis, the results of study 1 indicate that the recognition distances for the shapes are not significantly different. It may be concluded that the highly saturated colors are superior stimuli when earliest possible recognition of a reflectorized target under automobile low-beam illumination at night is important. This paper appears in transportation research record no. 1327, Visibility, rail-highway grade crossings, and highway improvement evaluation 1991
Abstract