The purpose of the present study is to verify the usability of physical qualities of ITS displays which convey various levels of criticality and urgency to drivers. Three experiments were conducted following previous research, which quantitatively clarified the contributions of each display determinant as interval scale scores; i.e., color-luminance, blinking, visual size, sound pressure level, tone frequency, and intermittence of tones. The first experiment was aimed at confirming the effects of each display quality on the subjective impressions when the visual and auditory displays were presented at the same time, and the simultaneous presentation effects were numerically estimated by adding the identical scores of each determinant. In the second experiment, the display qualities were directly compared to simple message words. And in the third experiment, the contributions of display qualities were examined in an actual driving situation. The results of the second and third experiments suggested that consideration of the display's physical qualities must be given preference over selection of words or symbols to convey the criticality and urgency of ITS information at a glance. (A*)
Abstract