Why should you inspect each unit's brakes individually rather than relying on a single overall air pressure check for the entire combination?

Pick an answer

1. A problem isolated to one trailer or dolly's brakes might not be obvious from a combination-wide reading alone
2. Only the tractor's brakes need individual checking in any combination
3. Individual unit brake checks are unnecessary once the combination holds overall air pressure across the whole system
4. Air pressure readings always reveal exactly which unit has a problem automatically

Correct!

Not quite. The correct answer is highlighted.