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CDL Doubles Triples Practice Questions - CDL Doubles Triples Endorsement (T) Exam
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Question
1
of 25
QUESTION 1 / 25
When coupling a tractor to the first semi-trailer in a double combination, at what height should the trailer be positioned?
Choose one answer below.
A
Higher than the tractor fifth wheel
✓
B
Slightly lower than the tractor fifth wheel
✓
C
At the same height as the tractor fifth wheel
✓
D
Height does not matter as long as the kingpin engages
✓
QUESTION 2 / 25
What is the correct procedure for connecting the air lines when coupling a trailer?
Choose one answer below.
A
Connect the emergency line first, then the service line
✓
B
Connect the service line first, then the emergency line
✓
C
Connect both lines simultaneously
✓
D
Connect only the service line; the emergency line is optional
✓
QUESTION 3 / 25
Before backing under a trailer to couple, what should you verify about the trailer brakes?
Choose one answer below.
A
That they are released
✓
B
That they are locked and/or wheels are chocked
✓
C
That they have been tested within the last hour
✓
D
That the brake shoes are new
✓
QUESTION 4 / 25
What should you check after coupling but before moving the vehicle?
Choose one answer below.
A
Only that the trailer lights work
✓
B
That the fifth wheel jaws have closed around the kingpin and the locking lever is in the lock position
✓
C
Only that the air lines are connected
✓
D
That the cargo is properly loaded
✓
QUESTION 5 / 25
When coupling the second trailer in a set of doubles, where should the converter dolly be positioned?
Choose one answer below.
A
At the front of the first semi-trailer
✓
B
At the rear of the first semi-trailer
✓
C
In the middle of the first semi-trailer
✓
D
Anywhere along the side of the first semi-trailer
✓
QUESTION 6 / 25
What is the purpose of the pintle hook on a converter dolly?
Choose one answer below.
A
To connect the air lines between trailers
✓
B
To connect the dolly to the front trailer
✓
C
To secure the dolly wheels during transport
✓
D
To hold the spare tire
✓
QUESTION 7 / 25
How can you release the converter dolly brakes when positioning the dolly for coupling?
Choose one answer below.
A
By using the tractor air system only
✓
B
By using the petcock or parking brake control on the dolly
✓
C
Converter dolly brakes cannot be released manually
✓
D
By disconnecting the air lines
✓
QUESTION 8 / 25
What should you do with the converter dolly support legs after coupling?
Choose one answer below.
A
Leave them down for extra stability
✓
B
Raise them completely and secure them in the raised position
✓
C
Lower them halfway to absorb shocks
✓
D
Remove them entirely
✓
QUESTION 9 / 25
When coupling a set of doubles, in what order should the air lines be connected to the rear trailer?
Choose one answer below.
A
Service line first, then emergency line
✓
B
Emergency line first, then service line
✓
C
Both lines at the same time
✓
D
It does not matter which line is connected first
✓
QUESTION 10 / 25
What is a "glad hand" in the context of doubles/triples operations?
Choose one answer below.
A
A type of wrench used for coupling
✓
B
The coupling device used to connect air lines between vehicles
✓
C
A safety glove worn during coupling
✓
D
The handle on the trailer landing gear
✓
QUESTION 11 / 25
What should you check before coupling to ensure the fifth wheel is in proper condition?
Choose one answer below.
A
Only that it is lubricated
✓
B
That the jaws operate freely, the locking mechanism works, and it is properly lubricated
✓
C
Only that it is the correct color
✓
D
That it is cold to the touch
✓
QUESTION 12 / 25
What happens if you attempt to move the vehicle before the trailer air tanks are fully charged?
Choose one answer below.
A
The trailer brakes will not release
✓
B
The engine will stall
✓
C
The trailer will automatically uncouple
✓
D
Nothing; the vehicle will operate normally
✓
QUESTION 13 / 25
When coupling the second trailer in a double combination, how should the trailer height be adjusted?
Choose one answer below.
A
The trailer should be higher than the dolly fifth wheel
✓
B
The trailer should be slightly lower than the dolly fifth wheel
✓
C
The trailer should be at the same height as the dolly fifth wheel
✓
D
Height adjustment is not necessary for the second trailer
✓
QUESTION 14 / 25
What is the purpose of the safety catch or lock on the pintle hook?
Choose one answer below.
A
To prevent the dolly from pivoting
✓
B
To prevent the drawbar from accidentally disengaging from the pintle hook
✓
C
To lock the dolly brakes
✓
D
To secure the air lines
✓
QUESTION 15 / 25
After connecting air lines to a trailer, what should you check for?
Choose one answer below.
A
Color matching between the lines
✓
B
Air leaks at the glad hand connections
✓
C
That the lines are the same length
✓
D
That the lines are touching the ground
✓
QUESTION 16 / 25
What is the proper technique for backing a converter dolly under a trailer?
Choose one answer below.
A
Back quickly to minimize time
✓
B
Back slowly and carefully, ensuring proper alignment
✓
C
Pull forward first, then back at an angle
✓
D
Have someone push the dolly into position
✓
QUESTION 17 / 25
What is the function of the drawbar on a trailer?
Choose one answer below.
A
To hold the spare tire
✓
B
To provide the connection point between trailers or between the dolly and trailer
✓
C
To support the trailer landing gear
✓
D
To carry electrical wiring
✓
QUESTION 18 / 25
When coupling a set of doubles, when should the landing gear of the second trailer be raised?
Choose one answer below.
A
Before backing the dolly under the trailer
✓
B
After the dolly is coupled and the air lines are connected
✓
C
It should never be raised
✓
D
Only when the trailer is fully loaded
✓
QUESTION 19 / 25
What type of kingpin is typically found on trailers designed for converter dolly use?
Choose one answer below.
A
A smaller diameter kingpin than standard
✓
B
A standard 2-inch diameter kingpin
✓
C
No kingpin is needed for dolly coupling
✓
D
A retractable kingpin
✓
QUESTION 20 / 25
What should be done with the electrical cable when coupling doubles?
Choose one answer below.
A
It is not needed for doubles
✓
B
Connect it only to the first trailer
✓
C
Connect it to both trailers in sequence
✓
D
Leave it disconnected to save battery power
✓
QUESTION 21 / 25
What is the first step in uncoupling the rear trailer of a set of doubles?
Choose one answer below.
A
Disconnect the air lines immediately
✓
B
Position the combination on level ground, apply the parking brakes, and lower the landing gear
✓
C
Release the pintle hook immediately
✓
D
Pull forward quickly to separate the trailers
✓
QUESTION 22 / 25
In what order should air lines be disconnected when uncoupling?
Choose one answer below.
A
Emergency line first, then service line
✓
B
Service line first, then emergency line
✓
C
Both lines simultaneously
✓
D
The order does not matter
✓
QUESTION 23 / 25
What should you do with the glad hands after disconnecting the air lines?
Choose one answer below.
A
Leave them hanging freely
✓
B
Secure them in a position where they will not become contaminated or damaged
✓
C
Connect them to each other between the two trailers
✓
D
Tape them to the trailer body
✓
QUESTION 24 / 25
Before releasing the fifth wheel latch to uncouple, what must be verified?
Choose one answer below.
A
That the trailer is empty
✓
B
That the trailer landing gear is fully lowered and making firm contact with the ground
✓
C
That the engine is running
✓
D
That the trailer brakes are released
✓
QUESTION 25 / 25
What happens when you pull the fifth wheel release lever?
Choose one answer below.
A
The trailer immediately detaches
✓
B
The fifth wheel jaws open, releasing the kingpin, but the trailer may not separate until the tractor moves
✓
C
The landing gear automatically lowers
✓
D
The trailer brakes release
✓
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