Investigation of Reasonable Information Load on Integrated Intersection-Approaching Signs

Integrated intersection-approaching sign (IIAS) is a unique type of sign which consists of a central pattern, multiple street names, and lane control arrows. It is a combination of the advance intersection lane control sign and the destination sign. In this research, computer-based legibility experiment is conducted by 40 recruited drivers. The experiment shows that the average reaction time for a complex pattern is five times of a lane control arrow. To simplify the design process of IIAS, an equivalent single arrow information load (ESAIL) is proposed. A lane control arrow, a street name, a simple central pattern, and a complex central pattern are quantified as 1, 5, 0, and 5 ESAIL, respectively. It is suggested that the total ESAIL should not exceed 30 for designing IIAS. Based on this proposal, recommendation of total street names, and lane control arrow number is made according to the type of the central pattern.