CDL - Combination Vehicle Practice Test Questions
And Answers
A tractor with a(n) ________ trailer requires the shortest amount of stopping distance .
1. empty
2. fully loaded
3. lightly loaded - ANSWER-fully loaded
The air leakage rate for a combination vehicle ( engine off, brakes on) should not be more than
_____ psi per minute .
1. 4
2. 6
3. 2 - ANSWER-4
If you do not do the final air brake check for air leaks and fix them before driving,
1. you could lose your brakes while driving
2. your fuel usage will increase
3. tire pressure will drop - ANSWER-you could lose your brakes while driving
Which part of the kingpin should the locking jaws close around? - ANSWER-The shank
Glad hands are used to connect the ....
1. kingpin from the trailer to the locking jaws of the fifth wheel
2. electrical lines from the tractor to the trailer
, 3. service and emergency air lines from the truck or tractor to the trailer - ANSWER-service and
emergency air lines from the truck or tractor to the trailer
Trucks roll over more easily when fully loaded and are
1. ten times more likely to roll over in a crash than empty rigs
2. five times more likely to roll over in a crash than empty rigs
3. two times more likely to roll over in a crash than empty rigs - ANSWER-ten times more likely
to roll over in a crash than empty rigs
In general, the higher your trucks center of gravity, the ...
1. easier it is to turn over
2. more stable it is when turning
3. easier it is to turn around corners - ANSWER-easier it is to turn over
You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines.
You would expect the trailer brakes to come on and ...
1. the tractor to lose all air pressure
2. the tractor protection valve to close
3. the trailer supply valve to stay open - ANSWER-the tractor protection valve to close
When you drive a set of doubles, which shut-off valve must be closed in the last trailer?
1. Middle section
2. front section
3. back section - ANSWER-back section
The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means
that...
And Answers
A tractor with a(n) ________ trailer requires the shortest amount of stopping distance .
1. empty
2. fully loaded
3. lightly loaded - ANSWER-fully loaded
The air leakage rate for a combination vehicle ( engine off, brakes on) should not be more than
_____ psi per minute .
1. 4
2. 6
3. 2 - ANSWER-4
If you do not do the final air brake check for air leaks and fix them before driving,
1. you could lose your brakes while driving
2. your fuel usage will increase
3. tire pressure will drop - ANSWER-you could lose your brakes while driving
Which part of the kingpin should the locking jaws close around? - ANSWER-The shank
Glad hands are used to connect the ....
1. kingpin from the trailer to the locking jaws of the fifth wheel
2. electrical lines from the tractor to the trailer
, 3. service and emergency air lines from the truck or tractor to the trailer - ANSWER-service and
emergency air lines from the truck or tractor to the trailer
Trucks roll over more easily when fully loaded and are
1. ten times more likely to roll over in a crash than empty rigs
2. five times more likely to roll over in a crash than empty rigs
3. two times more likely to roll over in a crash than empty rigs - ANSWER-ten times more likely
to roll over in a crash than empty rigs
In general, the higher your trucks center of gravity, the ...
1. easier it is to turn over
2. more stable it is when turning
3. easier it is to turn around corners - ANSWER-easier it is to turn over
You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines.
You would expect the trailer brakes to come on and ...
1. the tractor to lose all air pressure
2. the tractor protection valve to close
3. the trailer supply valve to stay open - ANSWER-the tractor protection valve to close
When you drive a set of doubles, which shut-off valve must be closed in the last trailer?
1. Middle section
2. front section
3. back section - ANSWER-back section
The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means
that...
