Which of the following is classified as a traffic control device?

Traffic control devices are essential tools used to manage and direct traffic flow to ensure safety and efficiency on roadways. Signs fall under this category as they communicate important information, instructions, or warnings to drivers and pedestrians. They provide vital information regarding speed limits, road conditions, directions, and other regulations, helping to inform and guide road users effectively.

In contrast, while road maintenance equipment, traffic police, and vehicles play significant roles in the transportation ecosystem, they do not serve the primary function of traffic control devices. Road maintenance equipment is used for repairs and upkeep of the roadway but does not communicate information to the public. Traffic police manage traffic flow and enforce laws, but they are personnel, not devices designed specifically for traffic management. Vehicles operate on roadways but are not meant to convey directives to other drivers or pedestrians. Thus, signs stand out as the correct answer because they are explicitly designed to control and inform traffic behavior.