NC CDL Combination Vehicles Exam
Questions And Answers
You are coupling a semi-trailer to your tractor but have not yet
backed under, the trailer is at the right height when: -
correct answer ✅It will be raised slightly when the tractor is
backed under it.
You should not back a tractor under a trailer until the whole air
system is: -
correct answer ✅At normal pressure.
Which part of the kingpin should the locking jaws close around? -
correct answer ✅The shank.
When you get ready to back under the semi-trailer you should line
up: -
correct answer ✅Directly in front of the trailer.
How should you test the tractor semi-trailer connection for
security? -
correct answer ✅Pull gently forward in low gear against the locked
trailer brakes, then look at it carefully.
,NC CDL Combination Vehicles Exam
Questions And Answers
When should you use the hand valve to park a combination
vehicle? -
correct answer ✅Never.
You supply air to the trailer tanks by: -
correct answer ✅Pushing in the trailer air supply valve.
Why should you be sure that the fifth wheel plate is greased as
required? -
correct answer ✅To prevent steering problems.
After you supply air to the trailer, make sure the air lines are not
crossed and the trailer brakes are working. This is done by: -
correct answer ✅Applying and releasing the trailer brakes and
listening for brake sounds.
There are two things that a driver can do to prevent a rollover. They
are: (1) Keep the cargo as close to the ground as possible; and (2): -
correct answer ✅Go slowly around turns.
Before you back under a trailer, make sure the: -
correct answer ✅Trailer brakes are locked.
, NC CDL Combination Vehicles Exam
Questions And Answers
If the service air line comes apart while you are driving a
combination vehicle, but the emergency line stays together, what
will happen right away? -
correct answer ✅Nothing is likely to happen until you try to apply
the brakes.
The air leakage rate for a combination vehicle (engine off, brakes
on) should not be more than ___ PSI per minute. -
correct answer ✅4
In normal driving, some drivers use the hand valve before applying
the brake pedal to prevent a jackknife. Which of these statements is
true? -
correct answer ✅If the trailer has not spring brakes, you can drive
away, but you will not have trailer brakes.
Why should you lock the tractor glad hands (or dummy couplers) to
each other when you are not towing a trailer? -
correct answer ✅It will keep dirt and water out of the lines.
Questions And Answers
You are coupling a semi-trailer to your tractor but have not yet
backed under, the trailer is at the right height when: -
correct answer ✅It will be raised slightly when the tractor is
backed under it.
You should not back a tractor under a trailer until the whole air
system is: -
correct answer ✅At normal pressure.
Which part of the kingpin should the locking jaws close around? -
correct answer ✅The shank.
When you get ready to back under the semi-trailer you should line
up: -
correct answer ✅Directly in front of the trailer.
How should you test the tractor semi-trailer connection for
security? -
correct answer ✅Pull gently forward in low gear against the locked
trailer brakes, then look at it carefully.
,NC CDL Combination Vehicles Exam
Questions And Answers
When should you use the hand valve to park a combination
vehicle? -
correct answer ✅Never.
You supply air to the trailer tanks by: -
correct answer ✅Pushing in the trailer air supply valve.
Why should you be sure that the fifth wheel plate is greased as
required? -
correct answer ✅To prevent steering problems.
After you supply air to the trailer, make sure the air lines are not
crossed and the trailer brakes are working. This is done by: -
correct answer ✅Applying and releasing the trailer brakes and
listening for brake sounds.
There are two things that a driver can do to prevent a rollover. They
are: (1) Keep the cargo as close to the ground as possible; and (2): -
correct answer ✅Go slowly around turns.
Before you back under a trailer, make sure the: -
correct answer ✅Trailer brakes are locked.
, NC CDL Combination Vehicles Exam
Questions And Answers
If the service air line comes apart while you are driving a
combination vehicle, but the emergency line stays together, what
will happen right away? -
correct answer ✅Nothing is likely to happen until you try to apply
the brakes.
The air leakage rate for a combination vehicle (engine off, brakes
on) should not be more than ___ PSI per minute. -
correct answer ✅4
In normal driving, some drivers use the hand valve before applying
the brake pedal to prevent a jackknife. Which of these statements is
true? -
correct answer ✅If the trailer has not spring brakes, you can drive
away, but you will not have trailer brakes.
Why should you lock the tractor glad hands (or dummy couplers) to
each other when you are not towing a trailer? -
correct answer ✅It will keep dirt and water out of the lines.
