When you couple a converter dolly to a lead trailer, you should:
Correct. Manage shut-off valves so air supply is restored to the rear trailer in proper sequence; verify with brake checks.
CDL Practice Question #391
Category: Doubles/Triples
Why this question matters
This question is one of 50 in our Doubles/Triples bank. The reasoning above comes directly from the AAMVA CDL Manual, the source document used by every U.S. state DMV. Memorizing the underlying rule — not just the letter answer — is what separates passing on the first attempt from a return trip and another fee.