CDL Combination Vehicles Exam
CDL Combination Vehicles Exam
Questions and Answers 2024
How should you test the tractor semi trailer combination for being properly coupled? -
Pull gently forward in low gear against the locked trailer brakes, then inspect your
coupling.
When coupling to the trailer, how far do you back up before stopping the first time? -
Until the fifth wheel plate just touches the trailer.
What do you check before backing under the trailer? - Make sure the trailer brakes are
set.
Air lines on a combination vehicle are often colored to keep them from getting mixed up.
What color is the emergency line and what color is the service line? - Red and blue.
After you back up to the trailer and the fifth wheel plate touches the trailer, you set the
tractor park brake, get out and hook up the emergency and service air lines. Then what
do you do before backing under the trailer? - Supply air to the trailer system, then pull
out the trailer air supply knob to fully set the trailer brakes.
What three things can you do to prevent rollovers? - Keep your load centered, keep the
load as low in the trailer as possible, and go slow around turns.
How far do you raise the landing gear on your trailer? - Crank it up as far as it will go.
You have coupled with a semi trailer. In what position should you put the landing gear
before driving away? - Fully raised with the crank handle secured in its bracket.
CDL Combination Vehicles Exam
, CDL Combination Vehicles Exam
When uncoupling, what could happen if you park the trailer at an angle? - You could do
damage to the landing gear and dolly legs.
Why should you lock the tractor glad hands together or couple them to the dummy glad
hands when bobtailing? - It will keep dirt and water out of the lines.
When backing under a trailer, you should expect the trailer to be lifted slightly by the fifth
wheel plate. - True.
Before you begin coupling, you should check your travel path for obstacles and
hazards. - True.
What should your air supply pressure gauge read before backing under a trailer? - 100 -
125 psi.
In case of a jackknife situation, you can use your trailer hand valve to apply trailer
brakes to stop the trailer from skidding. - False.
Which knob do you actuate to supply air to your trailer? - Push in on the tractor
protection valve knob, which is the red knob.
Do combination vehicles take longer to stop when they are empty or loaded? - When
they are empty.
What three things do you check after coupling to a trailer? - Check that there is no gap
between the fifth wheel plate and the trailer apron, check that the release handle is all
the way in and latched, and check with a flashlight that the fifth wheel jaws have locked
around the kingpin.
Bobtail tractors will stop shorter than a combination vehicle loaded to maximum gross
weight. - False.
CDL Combination Vehicles Exam
CDL Combination Vehicles Exam
Questions and Answers 2024
How should you test the tractor semi trailer combination for being properly coupled? -
Pull gently forward in low gear against the locked trailer brakes, then inspect your
coupling.
When coupling to the trailer, how far do you back up before stopping the first time? -
Until the fifth wheel plate just touches the trailer.
What do you check before backing under the trailer? - Make sure the trailer brakes are
set.
Air lines on a combination vehicle are often colored to keep them from getting mixed up.
What color is the emergency line and what color is the service line? - Red and blue.
After you back up to the trailer and the fifth wheel plate touches the trailer, you set the
tractor park brake, get out and hook up the emergency and service air lines. Then what
do you do before backing under the trailer? - Supply air to the trailer system, then pull
out the trailer air supply knob to fully set the trailer brakes.
What three things can you do to prevent rollovers? - Keep your load centered, keep the
load as low in the trailer as possible, and go slow around turns.
How far do you raise the landing gear on your trailer? - Crank it up as far as it will go.
You have coupled with a semi trailer. In what position should you put the landing gear
before driving away? - Fully raised with the crank handle secured in its bracket.
CDL Combination Vehicles Exam
, CDL Combination Vehicles Exam
When uncoupling, what could happen if you park the trailer at an angle? - You could do
damage to the landing gear and dolly legs.
Why should you lock the tractor glad hands together or couple them to the dummy glad
hands when bobtailing? - It will keep dirt and water out of the lines.
When backing under a trailer, you should expect the trailer to be lifted slightly by the fifth
wheel plate. - True.
Before you begin coupling, you should check your travel path for obstacles and
hazards. - True.
What should your air supply pressure gauge read before backing under a trailer? - 100 -
125 psi.
In case of a jackknife situation, you can use your trailer hand valve to apply trailer
brakes to stop the trailer from skidding. - False.
Which knob do you actuate to supply air to your trailer? - Push in on the tractor
protection valve knob, which is the red knob.
Do combination vehicles take longer to stop when they are empty or loaded? - When
they are empty.
What three things do you check after coupling to a trailer? - Check that there is no gap
between the fifth wheel plate and the trailer apron, check that the release handle is all
the way in and latched, and check with a flashlight that the fifth wheel jaws have locked
around the kingpin.
Bobtail tractors will stop shorter than a combination vehicle loaded to maximum gross
weight. - False.
CDL Combination Vehicles Exam
