During the air brake pre-trip check, why do you test how quickly the air compressor builds pressure?

Pick an answer

1. Build-up rate has no bearing on safe operation
2. It only matters on vehicles equipped with the older style of air compressor, which most training glosses over about pressure
3. It is checked only to estimate fuel economy
4. A compressor that builds pressure too slowly may not keep up with brake usage during driving

Correct!

Not quite. The correct answer is highlighted.