On a triple, the air pressure to the rearmost trailer:
Correct. Greater line length = greater brake-lag at the rear. Plan braking earlier than you would for a single trailer.
CDL Practice Question #374
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.