Which of the following describes the purpose of a regulatory sign?

The purpose of a regulatory sign is to control traffic flow and ensure safety on the road. These signs communicate the rules and regulations that drivers are required to follow to maintain order and minimize the risk of accidents. For instance, signs that indicate speed limits, stop signs, and yield signs are all essential for establishing the behavior of drivers on the roadway, making it clear what actions are necessary in different situations to protect all road users.

Regulatory signs help create a structured and predictable environment for driving, which is crucial for safety. They inform drivers of what is legally required of them to prevent chaos and ensure that everyone understands the traffic laws, thereby enhancing the overall efficiency of transportation systems.

The other options focus on different types of signs that serve other purposes. For example, signs that provide directions to services are meant to guide travelers, warnings of potential hazards alert drivers to specific dangers, and signs that guide cyclists are aimed at increasing safety for non-motorized users. Each of these serves important functions, but they do not encapsulate the primary role of regulatory signs.