What do white or black signs commonly represent in traffic control?

White or black signs are primarily used to convey regulatory information in traffic control. These signs include important directives that must be followed by drivers to ensure safety and proper traffic flow. For example, speed limit signs, which are typically white and black, indicate the maximum or minimum speed at which vehicles may legally travel on a roadway.

Regulatory signs are crucial because they inform drivers about what actions are permissible or required on the road. They serve to direct behavior in a way that maintains order and safety in traffic environments. In contrast, warning signs usually take on colors such as yellow or orange and are designed to alert drivers to potential hazards. Guidance signs, often green or blue, provide direction and distance information, helping navigate through intersections or along roadways. Prohibition signs, typically red, indicate actions that are not allowed but fall under the broader category of regulatory signs. Hence, the white or black signs' specific role in communication of regulations gives this answer its correctness.