New Jersey Air Brakes Practice Test

When should the parking brakes be used with air brake vehicles?

1. Only when the vehicle is moving

2. Whenever you leave the vehicle unattended

3. Only on steep downhill roads

4. When the brakes are hot

The correct answer is: Whenever you leave the vehicle unattended

The parking brakes should be used whenever you leave the vehicle unattended because they are designed to secure the vehicle in place and prevent it from rolling away. This is especially important with air brake vehicles, which can lose air pressure and automatically release their service brakes if left unmonitored. Engaging the parking brake provides a solid and reliable means of ensuring that the vehicle remains stationary while you step away, which is a critical safety consideration. Using the parking brakes only when the vehicle is moving, only on steep downhill roads, or when the brakes are hot does not appropriately address the need for securing the vehicle when parked. It's essential to prioritize vehicle safety in all situations, particularly when it is left unattended.