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CDL - Combination Vehicle Practice
Test| Certified Q&A 2026
You are uncoupling a trailer. After you shut off the trailer air supply and lock the
trailer brakes, you should
1. immediately apply your tractor parking brakes
2. begin to lower the trailer landing gear
3. back up gently and ease pressure on the fifth wheel locking jaws - correct-
answer - back up gently to ease pressure on the fifth wheel locking jaws
When should you use the hand valve to park a combination vehicle?
1. To park at loading docks
2. To park on a grade
3. never - correct-answer - Never
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The front trailer supports are up, and the trailer is resting on the tractor. Make
sure that
1. there is enough clearance between the upper and lower fifth wheel
2. there is enough clearance between the tractor frame and the landing gear
3. the safety latch is in the unlocked position - correct-answer - there is enough
clearance between the tractor frame and the landing gear
The trailer hand valve works the trailer brakes. Which of these statements is true?
1. the foot brake sends air to all the brakes on the vehicle ( including the trailer(s))
2. The trailer hand valve should be used only to test the trailer brakes
3. all the above - correct-answer - all the above
Where should the tractor be when you inspect the landing gear after uncoupling
the trailer?
1. With the fifth wheel directly beneath the kingpin
2. completely cleared from the trailer
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3. with the tractor frame under the trailer - correct-answer - with the tractor
frame under the trailer
After you lock the kingpin into the fifth wheel, you should check the connection
by pulling
1. the tractor ahead gently with the trailer brakes locked
2. forward 50 feet, then turning right, and then left
3. the tractor ahead sharply to release the trailer brakes - correct-answer - the
tractor ahead gently with the trailer brakes locked
At night, when a vehicle is carrying a load that extends four feet or more beyond
the rear of the body, there must be ________ at the extreme end of the load.
1. red lights
2. red flags
3. a red flag - correct-answer - red lights
CDL - Combination Vehicle Practice
Test| Certified Q&A 2026
You are uncoupling a trailer. After you shut off the trailer air supply and lock the
trailer brakes, you should
1. immediately apply your tractor parking brakes
2. begin to lower the trailer landing gear
3. back up gently and ease pressure on the fifth wheel locking jaws - correct-
answer - back up gently to ease pressure on the fifth wheel locking jaws
When should you use the hand valve to park a combination vehicle?
1. To park at loading docks
2. To park on a grade
3. never - correct-answer - Never
,2|Page
The front trailer supports are up, and the trailer is resting on the tractor. Make
sure that
1. there is enough clearance between the upper and lower fifth wheel
2. there is enough clearance between the tractor frame and the landing gear
3. the safety latch is in the unlocked position - correct-answer - there is enough
clearance between the tractor frame and the landing gear
The trailer hand valve works the trailer brakes. Which of these statements is true?
1. the foot brake sends air to all the brakes on the vehicle ( including the trailer(s))
2. The trailer hand valve should be used only to test the trailer brakes
3. all the above - correct-answer - all the above
Where should the tractor be when you inspect the landing gear after uncoupling
the trailer?
1. With the fifth wheel directly beneath the kingpin
2. completely cleared from the trailer
, 3|Page
3. with the tractor frame under the trailer - correct-answer - with the tractor
frame under the trailer
After you lock the kingpin into the fifth wheel, you should check the connection
by pulling
1. the tractor ahead gently with the trailer brakes locked
2. forward 50 feet, then turning right, and then left
3. the tractor ahead sharply to release the trailer brakes - correct-answer - the
tractor ahead gently with the trailer brakes locked
At night, when a vehicle is carrying a load that extends four feet or more beyond
the rear of the body, there must be ________ at the extreme end of the load.
1. red lights
2. red flags
3. a red flag - correct-answer - red lights
