CDL COMBINATION VEHICLE PRACTICE TEST
CERTIFICATION PAPER 2026 COMPLETE
SOLUTIONS GRADED A PLUS
◉ You have coupled with a semitrailer. Where should you put the
front trailer supports before driving away?
Answer: Fully raised with the crank handle secured in its bracket.
◉ If the spring brakes don`t release when you push the trailer air
supply control, you should:
Answer: Check the air line connections.
◉ When backing a tractor under a trailer you should:
Answer: Always use the lowest reverse gear
◉ How much space should be between the upper and lower fifth
wheel after coupling?
Answer: None
◉ A trailer most likely to jackknife when it is:
Answer: Empty
, ◉ When coupling, the proper position of the fifth wheel is:
Answer: Tilted down towards the end of the tractor
◉ You are coupling a tractor and semitrailer and have backed up but
are not under it. What should you hook up before backing under?
Answer: The emergency and service air lines
◉ How should you test the tractor-semitrailer connection for
security?
Answer: Pull gently forward in low gear against the locked trailer
brakes then look at it carefully
◉ A driver crosses the air lines when hooking up to an old trailer.
What will happen?
Answer: If the trailer has no spring brakes, he or she should drive
away but wouldn`t have trailer brakes
◉ The best way to tell if your trailer has started to skid is to:
Answer: See it in your mirrors
◉ When uncoupling a trailer, after you have shut off the trailer air
supply and locked the trailer brakes, you should:
Answer: Back up gently to ease pressure on the fifth wheel locking
jaws
CERTIFICATION PAPER 2026 COMPLETE
SOLUTIONS GRADED A PLUS
◉ You have coupled with a semitrailer. Where should you put the
front trailer supports before driving away?
Answer: Fully raised with the crank handle secured in its bracket.
◉ If the spring brakes don`t release when you push the trailer air
supply control, you should:
Answer: Check the air line connections.
◉ When backing a tractor under a trailer you should:
Answer: Always use the lowest reverse gear
◉ How much space should be between the upper and lower fifth
wheel after coupling?
Answer: None
◉ A trailer most likely to jackknife when it is:
Answer: Empty
, ◉ When coupling, the proper position of the fifth wheel is:
Answer: Tilted down towards the end of the tractor
◉ You are coupling a tractor and semitrailer and have backed up but
are not under it. What should you hook up before backing under?
Answer: The emergency and service air lines
◉ How should you test the tractor-semitrailer connection for
security?
Answer: Pull gently forward in low gear against the locked trailer
brakes then look at it carefully
◉ A driver crosses the air lines when hooking up to an old trailer.
What will happen?
Answer: If the trailer has no spring brakes, he or she should drive
away but wouldn`t have trailer brakes
◉ The best way to tell if your trailer has started to skid is to:
Answer: See it in your mirrors
◉ When uncoupling a trailer, after you have shut off the trailer air
supply and locked the trailer brakes, you should:
Answer: Back up gently to ease pressure on the fifth wheel locking
jaws
