Sign Shapes, Colors, and General Meaning
Shape and color are the first clue
Every sign in Arkansas follows the same national shape-and-color system. Learn the shape first, because it tells you the sign family before you can read the words. An octagon is always a stop sign. An inverted triangle is always yield. A diamond is a warning. A pentagon is a school zone or school crossing. A circle warns of a railroad crossing ahead. A crossbuck marks the crossing itself. A rectangle is used for regulatory and guide signs, and a pennant marks a no-passing zone.
Color reinforces the family. Red means stop, yield, or prohibition. Yellow means warning. Fluorescent yellow-green marks school, pedestrian, and bicycle warnings. Orange means construction or maintenance. Green is for guide and destination information. Blue is for motorist services. Brown is for recreation and cultural points. White with black text is usually regulatory; white on green or blue is guide.
The common trap is assuming every warning color is a command. A yellow diamond does not set a legal speed or order a turn; it tells you what is ahead. A white rectangular sign can be regulatory even though it looks plain. A red circle with a slash means the action shown is prohibited.
Worked example: a white rectangle reading SPEED LIMIT 55 is regulatory and enforceable. The same number on a yellow advisory plaque under a curve sign is a recommended speed, not the legal limit.
Rule of thumb: identify shape, then color, then message. If the sign orders or forbids an action, it is regulatory; if it cautions, it is warning.