Front-trailer (lead) wheels lock and the trailer behind continues forward — this is:
Correct. When the trailer wheels lose traction and the front-of-trailer pivots while the tractor continues forward, the result is a trailer jackknife.
CDL Practice Question #193
Category: Combination Vehicles
Why this question matters
This question is one of 55 in our Combination Vehicles 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.