What should every vehicle equipped with brakes ensure about the braking system?

The requirement that every vehicle equipped with brakes must have a braking system activated by one control device is rooted in ensuring the safety and efficiency of vehicle operation. When all brakes are operated through a single control device, it streamlined the driver's ability to manage braking, especially in critical situations where quick responses are necessary. This design reduces the complexity of control mechanisms, thereby lowering the risk of user error and ensuring that all brakes engage simultaneously, which is crucial for maintaining stability and control of the vehicle during braking maneuvers.

This concept is important for both safety and consistency. With a centralized control system, a driver can expect that activating the brakes will engage all braking components as intended, leading to predictable behavior of the vehicle. This is especially vital in emergency situations where the driver must react quickly.

In contrast, the other answer choices suggest a more complicated or less effective braking system design. Independent operation of brakes may introduce challenges with control and vehicle stability, while requiring two control devices could create confusion and lead to improper use. Thus, a system that ensures activation by one control device serves to reinforce best practices in vehicle safety and performance.