Arizona Air Brakes CDL Practice Test

When should parking brakes in air brake vehicles be used?

1. To hold your speed when going downhill

2. Whenever the vehicle is parked

3. As little as possible

4. Only during pre and post trip inspections

The correct answer is: Whenever the vehicle is parked

Parking brakes in air brake vehicles should be used whenever the vehicle is parked. This practice is crucial for ensuring safety and preventing unintentional movement of the vehicle when it is stationary. The parking brake acts as a reliable mechanism to secure the vehicle, especially on inclines or uneven terrains. Using the parking brake anytime the vehicle is parked helps prevent accidents that could occur if the vehicle were to roll away, potentially endangering people or property around it. It is standard protocol to engage the parking brake whenever the engine is turned off, regardless of the nature of the parking situation—whether on flat ground or a slope. Employing the parking brakes in this manner promotes responsible vehicle handling and compliance with safety regulations stipulated for commercial driving under air brake systems.