Why is selecting a low gear before starting down a long grade important for controlling an air brake vehicle?

Pick an answer

1. It only helps fuel economy
2. It has no effect except engine noise
3. Engine braking in a low gear helps control speed without relying solely on the brakes, which can overheat
4. It is only needed on sharp downhill curves, not straight sections of grade, since straight roads need no extra control

Correct!

Not quite. The correct answer is highlighted.