What must drivers do before driving a vehicle on a highway?

Before driving a vehicle on a highway, it is essential for drivers to demonstrate their capability of operating the vehicle type. This requirement ensures that the driver has the necessary skills and knowledge to handle the specific vehicle safely, especially considering the different characteristics of various vehicle types, such as size, weight, and control mechanisms.

Demonstrating capability often involves having prior training, experience, or specialized endorsements that indicate the driver can safely operate the vehicle. This is particularly critical for school bus drivers, who are responsible for the safety of children aboard their vehicles. By confirming that drivers can manage their vehicles effectively, road safety is prioritized, thereby reducing the risk of accidents.

The other options, such as completing a driving test, obtaining permission from Motor Carriers, or taking a written exam, may serve as additional steps in a driver's educational process or requirements for certain regulations but do not encompass the immediate necessity of demonstrating operating capability before driving on a highway.