-19-
RECOMMENDATION OF THE AMERICAN ASSOCIATION OF STATE HIGHWAY OFFICIALS REGARDING PRECAUTIONAL AND DIRECTIONAL SIGNS.
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 -
| (1) Railroad warning sign | Round | |
| (2) Danger or Stop sign | Octagonal | |
| (3) Caution or Slow sign | Diamond shaped | |
| (4) Look or Attention sign | Square | |
| (5) Road markers | Some characteristic or conventional shape different from the above. | |
| (6) Directional and Informational sign | Rectangular |
