It’s A Sign
With few exceptions road signs from state to state look the same. Categories are bunched by size and shape. In Texas, for example, as indicated by The Texas Department of Transportation:
Warning Signs are yellow and orange and are usually diamonds, pentagons and round. They indicate unexpected conditions or changes.
Regulatory Signs are red, black, and white usually triangles, octagons and vertical rectangles. They display traffic laws.
Signs That Guide are green, blue and brown usually horizontal rectangles and are used to provide helpful or interesting information.