What should a driver NOT do to hold a parked unit?

To hold a parked unit securely, a driver must utilize effective methods to prevent any unintentional movement. Setting the parking brake is standard practice as it engages the brakes of the vehicle, providing a primary means of securing it in place. Utilizing wheel chocks adds an additional layer of safety by physically blocking the wheels from rolling, which is especially important on inclines or uneven surfaces.

Engaging the drive axle brakes is a technique applicable in certain scenarios; however, using them as a standalone method can be less reliable when the vehicle is parked and not running.

In contrast, setting the trailer hand valve in an applied position is not a safe or standard way to secure a parked unit. The hand valve primarily controls the trailer brakes but does not serve as the primary method of securing the vehicle. It can be ineffective if the trailer is disconnected from a power source or if there is a failure in the valve system itself. Therefore, it is not recommended as the sole method for holding a parked unit.