New Jersey CDL — Air Brakes Practice Test 6

1.On a long, steep downgrade, how should the service brakes be used relative to the engine?

As the main way to hold speed, with the engine doing littleOnly to back up the slowing effect the engine already providesHeld down continuously the whole way down the hillNot at all until you reach the bottom of the grade

2.What is the main job of the air compressor on an air brake vehicle?

It builds and pushes air into the storage reservoirsIt measures how much pressure the brakes are applyingIt warns the driver when tank pressure gets lowIt automatically drains water from the tanks

3.What does the air compressor governor control?

How fast the vehicle is allowed to travelThe temperature of the brake drumsThe brightness of the low-pressure warning lightWhen the compressor starts and stops adding air to the tanks

4.When should you avoid setting the parking brakes and use wheel chocks instead?

Whenever the vehicle is fully loadedWhen the brakes are very hot, or very wet in freezing weatherAny time you park on level groundOnly when the engine is still running

5.What happens to the applied braking force as you push the brake (foot) pedal down harder?

The force stays exactly the same no matter how hard you pressMore air pressure is applied to the brakesThe parking brakes engage insteadThe compressor shuts off automatically

6.What should you conclude if the air system's safety valve lets air escape?

Something is wrong and it should be repaired by a mechanicThe system is working perfectly and no action is neededThe tanks simply need to be drained of waterThe compressor cut-in pressure is set too low

7.Which brake system operates when you press the pedal during ordinary driving?

The emergency brake systemThe service brake systemThe parking brake systemThe trailer hand-valve system

8.What is the key idea behind the "controlled braking" method?

Apply the brakes as hard as possible without locking the wheels, keeping steering smallLock the wheels immediately and steer hard around the hazardCoast in neutral and use only the engine to slow downAlternate the brakes and accelerator to keep the vehicle balanced

9.What does a supply pressure gauge on an air brake vehicle show the driver?

The outside air temperatureHow much pressure is being held in the air tanksThe distance needed to stop the vehicleThe engine's oil level

10.How do you perform the "stab braking" method in an emergency stop?

Press the pedal down gently and hold steady pressurePump the pedal lightly to keep the wheels barely turningApply the parking brake in short bursts instead of the pedalBrake fully, release when the wheels lock, then reapply fully once they roll