What is the function of a vertical rectangle-shaped sign?

A vertical rectangle-shaped sign primarily serves a regulatory function. These signs are designed to inform drivers of specific laws, regulations, and rules that must be followed in order to ensure safe driving practices on the road. For instance, they might indicate speed limits, no parking zones, or other important instructions that govern the behavior of vehicles and drivers.

In contrast, informational or guide signs typically provide directions or general information and usually come in different shapes, such as a horizontal rectangle or diamond. Traffic control signs can encompass a variety of shapes and types, and while they may include regulatory signs, they also cover others like stop signs and yield signs which have distinct shapes. Warning signs, on the other hand, are often shaped like triangles and are meant to alert drivers to potential hazards or changes in road conditions. Each sign shape serves a specific purpose, but the vertical rectangle is uniquely designated for regulatory messages.