This sign shall have a yellow-green background with black legend and border in accordance with the MUTCD.
The standard says: "
School warnings signs, including the "SCHOOL" portion of the School Speed Limit (S5-1) sign and including any supplemental plaques used in association with these warning signs, shall have a fluorescent yellow-green background with black legend and border unless otherwise provided in this manual for a specific sign.
See Section 1A.12 (03) on page 10 of the MUTCD for all traffic control devices.
The general meaning of the 13 colors shall be as follows:
B. Blue—road user services guidance, tourist information, and evacuation route
C. Brown—recreational and cultural interest area guidance
E. Fluorescent Pink—incident management
F. Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus and school warning
G. Green—indicated movements permitted, direction guidance
H. Light Blue—unassigned
I. Orange—temporary traffic control
J. Purple—lanes restricted to use only by vehicles with registered electronic toll collection (ETC) accounts
K. Red—stop or prohibition