What does an air dryer do in a modern air brake system?

Pick an answer

1. It removes moisture from the compressed air before it reaches the storage tanks
2. It dries the exterior of the vehicle after washing, confusing its name with a completely unrelated exterior task
3. It only functions when the parking brake is engaged, not while driving
4. It replaces the need to ever drain tanks

Correct!

Not quite. The correct answer is highlighted.