Optimum Number of Display Colors with Traffic Information Board

Abstract

Traffic information boards have a vital role in promoting safety and efficient road traffic, by providing the drivers with relevant traffic information on a real-time basis. To achieve good visibility and eye-catching quality, we must know the optimum number of display colors and ranges of chromaticity so that the road users can correctly recognize displayed information in a short time.
We attempted to determine the optimum number of display colors based on the categorical color (basic perceived color) technique, as well as to define the chromaticity regions for display colors so that a given color is most effectively discriminated from the others.
The results showed that the optimum number of display colors is nine, and categorization of the so-defined nine display colors on the chromaticity diagram is extremely useful in designing a traffic information board.