EVALUATION OF HIGH-INTENSITY SHEETING FOR OVERHEAD HIGHWAY SIGNS

The purpose of this research was to determine the feasibility of using high-intensity sheeting on overhead highway signs without external illumination. The brighness of five high-intensity overhead signs without illumination was compared with that of five conventional signs with illumination. All experimentation was conducted in the field under the physical and environmental conditions experienced by the highway user. Luminance measurements were made with a telephotometer at the driver's eye position in 11 domestic automobiles. A total of 4821 luminance measurements were recoreded from the travel lanes of illuminated and nonilluminated roadways. It was concluded that external lighting can be eliminated through the use of high-intensity sheeting on many overhead signs without adversely affecting the service to motorists. /Author/