Home › CDL Practice Tests › Combination Vehicles Questions › Question 53
You uncouple on a slight slope and the trailer begins to roll slowly as you pull clear. What error most likely led to this?
- A.The landing gear was raised too high
- B.The electrical cord was removed too early
- C.The fifth wheel had too much grease
- D.The trailer brakes were not set or the wheels were not chocked before uncoupling
Correct answer
D. The trailer brakes were not set or the wheels were not chocked before uncoupling
Why
Holding a trailer on a grade is the job of its brakes or chocks, not its landing gear. Failing to set them before releasing the tractor's control is the classic cause of a rolling dropped trailer.
Manual topic: Combination Vehicles - Uncoupling · From the Combination Vehicles practice bank (CV-053).