CDL Combination Test
"Bobtail" tractors can take longer to stop than a combination vehicle loaded to the maximum
gross weight - ANS-Which of these statements is true?
10 - ANS-Under good driving conditions, you should leave at least one second of space
between your vehicle and the ahead for every ___ feet of your vehicle's length.
20 and 45 - ANS-The trailer air supply control (also called the tractor prevention valve control)
should automatically close when the air pressure fails to, between ____ psi
3 - ANS-The air leakage rate for a combination vehicle (engine off, brakes off) should be no
more than _____ psi per minute.
4 - ANS-The air leakage rate for a combination vehicle (engine off, brakes on) should not be
more than _______ psi per minute
90 degrees - ANS-When connecting the glad hands press the two seals with the couplers
together at what degree to each other?
A pin which locks the trailer to the tractor on the fifth wheel - ANS-A king pin is:
Always use the lowest reverse gear - ANS-When backing a tractor under a trailer you should:
Apply the brakes as hard as you can without locking the wheels - ANS-Emergency controlled
braking is when you:
Applying and releasing the trailer brakes and listening for brake sounds - ANS-After you supply
air to the trailer, make sure the airlines are not crossed and the trailer brakes are working. This
is done by:
Applying and releasing the trailer brakes and listening for brake sounds; and also by lifting the
brake pedal - ANS-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:
At normal pressure - ANS-You have pushed in the trailer supply valve. You should not move the
tractor until the whole air system is:
At normal pressure - ANS-You should not back a tractor under a trailer until the whole air
system is:
, Back - ANS-When driving a set of doubles, it is necessary to close which shut-off valve in the
last trailer.
Back under the trailer at an angle - ANS-You can damage the landing gear if you:
Back up gently to ease pressure on the fifth wheel locking jaws - ANS-You are uncoupling a
trailer. After you shut off the trailer air supply and lock the trailer brakes, you should:
By seeing it in your mirrors - ANS-The earliest way to notice a trailer skid is:
Check air line connection - ANS-If the brakes are not released when you pushed the trailer air
supply valve you should:
Check your path for hazards - ANS-Before you begin coupling:
Completely cleared from the trailer - ANS-Where should the tractor be when you inspect landing
gear after uncoupling the trailer?
Connect the air supply lines - ANS-Which of the following steps comes first?
Couple the glad hands together; Couple the glad hands to dummy couplers; Hag the electrical
cable with the plug end down - ANS-When uncoupling, it's generally good practice to:
Cross air supply lines to test them for leaks - ANS-When coupling the glad hands, you should
NOT do the following:
Directly in front of the trailer - ANS-When you get ready to back under the semi-trailer you
should line up
easier it is to turn over - ANS-In general, the higher your trucks "center of gravity" the:
Emergency - ANS-The tractor protection valve will close and the trailer emergency brakes will
come on when there is a major break leak in the ___ brake line.
Emergency - ANS-When checking the trailer emergency brakes, the tractor protection control
valve should be placed in what position?
Fully raised with the crank handle secured in its bracket - ANS-You have coupled with a
semi-trailer. In what position should you put the front trailer supports before driving away?
Glad hands - ANS-A device which connects the service and emergency air lines from the truck
to the trailer is called..
"Bobtail" tractors can take longer to stop than a combination vehicle loaded to the maximum
gross weight - ANS-Which of these statements is true?
10 - ANS-Under good driving conditions, you should leave at least one second of space
between your vehicle and the ahead for every ___ feet of your vehicle's length.
20 and 45 - ANS-The trailer air supply control (also called the tractor prevention valve control)
should automatically close when the air pressure fails to, between ____ psi
3 - ANS-The air leakage rate for a combination vehicle (engine off, brakes off) should be no
more than _____ psi per minute.
4 - ANS-The air leakage rate for a combination vehicle (engine off, brakes on) should not be
more than _______ psi per minute
90 degrees - ANS-When connecting the glad hands press the two seals with the couplers
together at what degree to each other?
A pin which locks the trailer to the tractor on the fifth wheel - ANS-A king pin is:
Always use the lowest reverse gear - ANS-When backing a tractor under a trailer you should:
Apply the brakes as hard as you can without locking the wheels - ANS-Emergency controlled
braking is when you:
Applying and releasing the trailer brakes and listening for brake sounds - ANS-After you supply
air to the trailer, make sure the airlines are not crossed and the trailer brakes are working. This
is done by:
Applying and releasing the trailer brakes and listening for brake sounds; and also by lifting the
brake pedal - ANS-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:
At normal pressure - ANS-You have pushed in the trailer supply valve. You should not move the
tractor until the whole air system is:
At normal pressure - ANS-You should not back a tractor under a trailer until the whole air
system is:
, Back - ANS-When driving a set of doubles, it is necessary to close which shut-off valve in the
last trailer.
Back under the trailer at an angle - ANS-You can damage the landing gear if you:
Back up gently to ease pressure on the fifth wheel locking jaws - ANS-You are uncoupling a
trailer. After you shut off the trailer air supply and lock the trailer brakes, you should:
By seeing it in your mirrors - ANS-The earliest way to notice a trailer skid is:
Check air line connection - ANS-If the brakes are not released when you pushed the trailer air
supply valve you should:
Check your path for hazards - ANS-Before you begin coupling:
Completely cleared from the trailer - ANS-Where should the tractor be when you inspect landing
gear after uncoupling the trailer?
Connect the air supply lines - ANS-Which of the following steps comes first?
Couple the glad hands together; Couple the glad hands to dummy couplers; Hag the electrical
cable with the plug end down - ANS-When uncoupling, it's generally good practice to:
Cross air supply lines to test them for leaks - ANS-When coupling the glad hands, you should
NOT do the following:
Directly in front of the trailer - ANS-When you get ready to back under the semi-trailer you
should line up
easier it is to turn over - ANS-In general, the higher your trucks "center of gravity" the:
Emergency - ANS-The tractor protection valve will close and the trailer emergency brakes will
come on when there is a major break leak in the ___ brake line.
Emergency - ANS-When checking the trailer emergency brakes, the tractor protection control
valve should be placed in what position?
Fully raised with the crank handle secured in its bracket - ANS-You have coupled with a
semi-trailer. In what position should you put the front trailer supports before driving away?
Glad hands - ANS-A device which connects the service and emergency air lines from the truck
to the trailer is called..
