CDL COMBINATION TEST QUESTIONS
WITH CORRECT ANSWERS 2025-
2026
If you cross connect the two air lines the following will result - CORRECT ANSWER-
You will not have air going to the trailer brakes
You have coupled with a semi-
trailer. In what position should you put the front trailer supports before driving away? -
CORRECT ANSWER-Fully raised with the crank handle secured in its bracket
Th trailer air supply control: - CORRECT ANSWER-Is a red, eight sided knob
A device which connects the service and emergency air lines from the truck to the trailer is
called.. - CORRECT ANSWER-Glad hands
If one of the glad hands on your blue air line is missing a seal: - CORRECT ANSWER-
You might end up with a service line air leak
In order to supply air to the trailer, you must first: - CORRECT ANSWER-
Stop engine so you can hear the brakes
The hand valve should be used: - CORRECT ANSWER-To test the trailer brakes
The air leakage rate for a combination vehicle (engine off, brakes on) should not be more t
han psi per minute - CORRECT ANSWER-4
When should you use the hand valve to park a combination vehicle? - CORRECT ANSWER-
Never
, When you get ready to back under the semi-trailer you should line up - CORRECT ANSWER-
Directly in front of the trailer
If the service air line comes apart while you are driving a combination vehicle but the emer
gency line stays together, what will happen right away - CORRECT ANSWER-
Nothing is likely to happen until you try to apply the brakes
When uncoupling, if you park the trailer at an angle... - CORRECT ANSWER-
You could do damage to the landing gear
Which of these statements is true? - CORRECT ANSWER-
"Bobtail" tractors can take longer to stop than a combination vehicle loaded to the maximu
m gross weight
In normal driving, some drivers use the hand valve before applying the brake pedal to prev
ent a jackknife. Which of these statements is true? - CORRECT ANSWER-
It should not be done
When you inspect the coupling, check to ensure that: - CORRECT ANSWER-
There's a little slack in the air lines
When backing under a tractor under a trailer you should expect: - CORRECT ANSWER-
Trailer will be lifted slightly when the tractor back under it
A king pin is: - CORRECT ANSWER-
A pin which locks the trailer to the tractor on the fifth wheel
The safety catch for the fifth wheel locking level must be for a coupling to be comp
lete. - CORRECT ANSWER-Over the locking lever
WITH CORRECT ANSWERS 2025-
2026
If you cross connect the two air lines the following will result - CORRECT ANSWER-
You will not have air going to the trailer brakes
You have coupled with a semi-
trailer. In what position should you put the front trailer supports before driving away? -
CORRECT ANSWER-Fully raised with the crank handle secured in its bracket
Th trailer air supply control: - CORRECT ANSWER-Is a red, eight sided knob
A device which connects the service and emergency air lines from the truck to the trailer is
called.. - CORRECT ANSWER-Glad hands
If one of the glad hands on your blue air line is missing a seal: - CORRECT ANSWER-
You might end up with a service line air leak
In order to supply air to the trailer, you must first: - CORRECT ANSWER-
Stop engine so you can hear the brakes
The hand valve should be used: - CORRECT ANSWER-To test the trailer brakes
The air leakage rate for a combination vehicle (engine off, brakes on) should not be more t
han psi per minute - CORRECT ANSWER-4
When should you use the hand valve to park a combination vehicle? - CORRECT ANSWER-
Never
, When you get ready to back under the semi-trailer you should line up - CORRECT ANSWER-
Directly in front of the trailer
If the service air line comes apart while you are driving a combination vehicle but the emer
gency line stays together, what will happen right away - CORRECT ANSWER-
Nothing is likely to happen until you try to apply the brakes
When uncoupling, if you park the trailer at an angle... - CORRECT ANSWER-
You could do damage to the landing gear
Which of these statements is true? - CORRECT ANSWER-
"Bobtail" tractors can take longer to stop than a combination vehicle loaded to the maximu
m gross weight
In normal driving, some drivers use the hand valve before applying the brake pedal to prev
ent a jackknife. Which of these statements is true? - CORRECT ANSWER-
It should not be done
When you inspect the coupling, check to ensure that: - CORRECT ANSWER-
There's a little slack in the air lines
When backing under a tractor under a trailer you should expect: - CORRECT ANSWER-
Trailer will be lifted slightly when the tractor back under it
A king pin is: - CORRECT ANSWER-
A pin which locks the trailer to the tractor on the fifth wheel
The safety catch for the fifth wheel locking level must be for a coupling to be comp
lete. - CORRECT ANSWER-Over the locking lever
