What type of sign is used to indicate actions that are not allowed?

Regulatory signs are used specifically to indicate actions that are not allowed or must be followed while driving. These signs provide important instructions and rules that govern vehicle operation, ensuring the safety of all road users. Examples of regulatory signs include stop signs, yield signs, no parking signs, and speed limit signs. By conveying clear mandates, regulatory signs help in maintaining order on the roads and minimizing confusion among drivers.

In contrast, warning signs are designed to alert drivers to potential hazards or changes in road conditions, such as curves, intersections, or constructions areas. Pavement markings, such as lane lines and symbols, are used to convey information visually on the road surface, while guidance signs assist drivers with information regarding routes, directions, and distances. Each of these sign types serves distinct purposes, but regulatory signs are the only group that explicitly forbids or mandates certain actions, making them the correct choice for indicating prohibited behavior.