On a vehicle equipped with an application pressure gauge, what does it mean if you notice you need increasing application pressure to hold the same speed down a grade?

The parking brake has engaged automatically

The air tanks are overfilled and need to be drained

The ABS malfunction lamp will illuminate within seconds

Braking Technique, Stopping Distance &... Test

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Correct!

Correct. The AAMVA manual explains the application pressure gauge shows how much air pressure is being applied to the brakes, and increasing application pressure needed to hold the same speed means the brakes are fading; the driver should slow down and use a lower gear. Increased pressure needed can also be caused by brakes out of adjustment, air leaks, or mechanical problems.

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Not quite.

Incorrect. The parking brake is controlled manually by the parking control knob or lever and does not engage automatically based on application pressure readings; this describes an unrelated mechanism.

The correct answer is A: The brakes are fading, so you should slow down and use a lower gear.

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Not quite.

Incorrect. Overfilled air tanks are not a documented condition in the manual, and tank drains exist to remove water/oil contamination, not excess air pressure, which is managed by the governor and safety valve.

The correct answer is A: The brakes are fading, so you should slow down and use a lower gear.

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Not quite.

Incorrect. The ABS malfunction lamp is tied to the antilock braking system's electronic diagnostics, not to application pressure readings on the gauge, and nothing in the manual connects the two.

The correct answer is A: The brakes are fading, so you should slow down and use a lower gear.