The figure shows the layout of a word message R10-23a sign that is 30 inches wide and 36 inches tall. The top 8 inches of the sign has a black legend and border on a yellow background and the legend says CROSSWALK. The bottom 28 inches of the sign has a black legend and border on a white background and the legend says STOP ON RED followed by a horizontal line and then PROCEED ON FLASHING RED WHEN CLEAR. Detailed dimensioning for the lettering is also shown on the figure.
United States Department of Transportation - Federal Highway Administration