What is a key sign that indicates a school zone?

A yellow diamond-shaped sign is a key indicator of a school zone because this specific sign shape and color combination is recognized for warning drivers about potential hazards and changes in driving conditions, particularly in areas where children are likely to be present. The use of yellow serves to alert drivers to take caution and reduce speed as they approach the zone. This visual cue effectively communicates that they should be especially vigilant for children crossing the street or for other school-related activities.

The other shapes and colors correspond to different types of traffic signs; for example, a red octagonal sign is universally recognized as a stop sign, indicating that drivers must come to a complete stop. A green rectangular sign typically provides directional or informational guidance rather than serving as a warning. Meanwhile, a blue circular sign often indicates services or points of interest but does not relate specifically to the context of school zones. Therefore, the yellow diamond-shaped sign distinctly identifies areas where extra caution is necessary, particularly near schools.