What type of sign would indicate a maximum speed limit on a road?

The type of sign that indicates a maximum speed limit on a road is classified as a prohibitive sign. Prohibitive signs are designed to communicate restrictions or regulations to drivers, making them aware of legal limits or actions they must adhere to while on the road. The maximum speed limit is a critical piece of information that ensures the safety of all road users and helps maintain traffic flow.

In contrast, warning signs serve to alert drivers to potential hazards or changes in road conditions, and directional signs provide guidance on routes and navigation, while informative signs typically convey general information rather than regulatory limits. Therefore, prohibitive signs specifically focus on restrictions, making them the appropriate category for speed limit indications.