What feature is common to all regulatory signs?

Regulatory signs are designed to inform drivers about specific laws and regulations they must follow on the road. These signs play a critical role in maintaining safety and order in traffic by clearly stating the rules that govern vehicle operation. For example, a stop sign mandates that a driver must come to a complete stop at an intersection, while a speed limit sign indicates the maximum allowable speed on a particular stretch of roadway.

The essence of regulatory signs lies in their function to communicate enforceable commands or prohibitions. This characteristic differentiates them from warning signs, which alert drivers to potential hazards, and informational signs, which provide direction or point out attractions. By focusing specifically on laws, regulatory signs uphold the legal framework that supports safe driving practices.