When pulling a single trailer and trying to figure out if you should add a doubles endorsement:
Correct. The T endorsement is required only when you actually operate doubles or triples. Single-trailer operations do not require it.
CDL Practice Question #371
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.