Which of the following is a key purpose of traffic control devices?

The key purpose of traffic control devices is to facilitate the efficient and safe movement of road users. They are designed to communicate important information, instructions, or warnings to drivers, pedestrians, and cyclists. By doing so, these devices help maintain an orderly flow of traffic, enhance safety, and reduce the likelihood of accidents.

In this context, commanding respect from road users signifies establishing authority and compliance with traffic regulations. When road users respect and adhere to the information conveyed by traffic control devices, it promotes overall safety and enhances the effectiveness of the road system. This respect is crucial for reducing conflicts between different types of road users, thereby ensuring that everyone can navigate roadways safely.

Other options, like occupying road space or increasing travel speed, do not accurately reflect the primary intentions of traffic control devices, which focus on safety and regulation rather than mere physical presence or encouraging faster travel. Limiting vehicle access may be relevant in specific scenarios, such as during road construction or in certain zones, but it is not a generalized purpose of traffic control devices.