Page:Report of Joint Board on Interstate Highways.pdf/20

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It is recommended that this Association go on record as approving the following: A. For luminous signs or signals - (1) Red to indicate danger or stop. (2) Yellow to indicate caution or slow. (3) Green to indicate go.

B. For non-luminous signs - In view of the fact that the effectiveness of non-luminous signs depends upon visibility at night under automobile headlights, we recommend the use of a light background, preferably lemon yellow, with black lettering as a color scheme for these signs. The present knowledge of other color combinations does not justify a further recommendation at this time.

C. Shapes of non-luminous signs -