What specific type of traffic sign gives a driver a rule that they must follow?

The specific type of traffic sign that gives a driver a rule they must follow is a Regulatory Sign. A Regulatory Sign is designed to inform road users of traffic laws or regulations that are mandatory and legally enforceable. These signs explicitly command drivers to take a specific action, such as stopping or yielding, or prohibit them from certain actions, like exceeding a speed limit or making a turn. Disobeying a Regulatory Sign constitutes a traffic violation. While many regulatory signs are white rectangles with black lettering or symbols, some critical ones have unique shapes and colors to enhance recognition. For instance, the "STOP" sign is a red octagon with white lettering, commanding a complete stop before proceeding safely. The "YIELD" sign is a red and white inverted triangle, instructing drivers to slow down and give way to other traffic. A "SPEED LIMIT" sign, typically a white rectangle with black text, indicates the maximum legal speed allowed. "DO NOT ENTER" signs are red squares with a white bar and text, prohibiting entry into a specific area. "ONE WAY" signs, often white rectangles with black text and an arrow, indicate that traffic flows in only a single direction. Each of these examples communicates a direct and binding rule that drivers are legally obligated to obey.