CDL Combination Practice Test Questions
with Correct Answers
You're hooking up a tractor to a semi-trailer and have backed
up but are not under it. What should you do before backing
under the trailer? - Correct Answer ✅ Hook up the
emergency and service air lines.
After pushing in the trailer supply valve, you should not move
the tractor
until air system is? - Correct Answer ✅ At normal pressure
There are two things you can do to prevent a rollover. They
are: Keep the cargo as close to the ground as possible, and: -
Correct Answer ✅ Reduce speed before entering turns.
With the engine off and the brakes released, a combination
vehicle air brake system shouldn't leak more than how many
psi in one minute? - Correct Answer ✅ 3 psi
The fifth wheel locking lever isn't locked after the jaws close
around the kingpin. This means that: - Correct Answer ✅
The coupling is not correct and should be corrected before
driving the coupled unit.
with Correct Answers
You're hooking up a tractor to a semi-trailer and have backed
up but are not under it. What should you do before backing
under the trailer? - Correct Answer ✅ Hook up the
emergency and service air lines.
After pushing in the trailer supply valve, you should not move
the tractor
until air system is? - Correct Answer ✅ At normal pressure
There are two things you can do to prevent a rollover. They
are: Keep the cargo as close to the ground as possible, and: -
Correct Answer ✅ Reduce speed before entering turns.
With the engine off and the brakes released, a combination
vehicle air brake system shouldn't leak more than how many
psi in one minute? - Correct Answer ✅ 3 psi
The fifth wheel locking lever isn't locked after the jaws close
around the kingpin. This means that: - Correct Answer ✅
The coupling is not correct and should be corrected before
driving the coupled unit.
