CDL COMBINATION VEHICLE EXAM, PRACTICE EXAM
AND STUDY GUIDE NEWEST 2024 ACTUAL EXAM 300
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
(VERIFIED ANSWERS) |ALREADY GRADED A
You supply air to the trailer tanks by:
A: pushing in the trailer air supply valve
B: pulling out the trailer air supply valve
C: connecting the service air line - answer-Pushing in the trailer air supply valve.
Loss of air pressure in the emergency line causes:
A: the relay valves to close
B: an increase in air pressure to the service line
C: the trailer's emergency brakes to come on - answer-the trailer's emergency
brakes to come on
A tractor with a ___trailer requires the shortest amount of stopping distance.
A: empty
B: lightly loaded
C: fully loaded - answer-fully loaded
Which of these statements are true?
A. the brake and suspension of combination vehicles work best with a light load
B: light vehicles need more braking power to stop than heavy ones
C: bobtails tractor can take longer to stop than fully loaded combination vehicles -
answer-bobtails tractor can take longer to stop than fully loaded combination
vehicles
,If you cannot make a right turn without swinging into another lane, you should:
A: swing wide before you make the turn
B: turn wide as you complete the turn
C: not make that turn. Go to another place to turn. - answer-turn wide as you
complete the turn
The tractor protection valve will close and the trailer emergency brakes will come
on when there is a major leak in what air line?
A: service
B: emergency
C: parking - answer-emergency
Off tracking or "cheating" causes which of these to follow the widest path while
making a turn?
A: 3 axle tractor towing a 45 foot trailer
B: 3 axle tractor towing two 27 foot trailers
C: A bobtail tractor - answer-3 axle tractor towing a 45 foot trailer
If your vehicle gets stuck on a railroad crossing, you should:
A: use reverse to back of the tracks
B: get out of the vehicle and away from the tracks
C: turn on your 4-way flashers - answer-get out of the vehicle and away from the
tracks
, When driving a set of double trailers, it is necessary to close shut-off valves on
some trailers. Where are these valves located?
A: in the front of trailers
B: in the middle
C: at the back of trailers used to tow other trailers - answer-at the back of trailers
used to tow other trailers
Before you back under a trailer, make sure of what?
A: the trailer brakes are locked
B: the air supply knob is in
C: the air brakes are off - answer-the trailer brakes are locked
To unlock the fifth wheel, you pull the handle to what position?
A: open
B: neutral
C: closed - answer-open
After connecting the air lines but before backing under the trailer, you should:
A: supply air to the trailer, then pull out the trailer air supply valve
B: make sure that the trailer brakes are off
C.: walk around the rig to be sure it is clear - answer-supply air to the trailer, then
pull out the trailer air supply valve
You are coupling a tractor to a semi-trailer and you have backed up but are not
yet under it. What should you hook up before backing under it?
A: the emergency and service air lines
AND STUDY GUIDE NEWEST 2024 ACTUAL EXAM 300
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
(VERIFIED ANSWERS) |ALREADY GRADED A
You supply air to the trailer tanks by:
A: pushing in the trailer air supply valve
B: pulling out the trailer air supply valve
C: connecting the service air line - answer-Pushing in the trailer air supply valve.
Loss of air pressure in the emergency line causes:
A: the relay valves to close
B: an increase in air pressure to the service line
C: the trailer's emergency brakes to come on - answer-the trailer's emergency
brakes to come on
A tractor with a ___trailer requires the shortest amount of stopping distance.
A: empty
B: lightly loaded
C: fully loaded - answer-fully loaded
Which of these statements are true?
A. the brake and suspension of combination vehicles work best with a light load
B: light vehicles need more braking power to stop than heavy ones
C: bobtails tractor can take longer to stop than fully loaded combination vehicles -
answer-bobtails tractor can take longer to stop than fully loaded combination
vehicles
,If you cannot make a right turn without swinging into another lane, you should:
A: swing wide before you make the turn
B: turn wide as you complete the turn
C: not make that turn. Go to another place to turn. - answer-turn wide as you
complete the turn
The tractor protection valve will close and the trailer emergency brakes will come
on when there is a major leak in what air line?
A: service
B: emergency
C: parking - answer-emergency
Off tracking or "cheating" causes which of these to follow the widest path while
making a turn?
A: 3 axle tractor towing a 45 foot trailer
B: 3 axle tractor towing two 27 foot trailers
C: A bobtail tractor - answer-3 axle tractor towing a 45 foot trailer
If your vehicle gets stuck on a railroad crossing, you should:
A: use reverse to back of the tracks
B: get out of the vehicle and away from the tracks
C: turn on your 4-way flashers - answer-get out of the vehicle and away from the
tracks
, When driving a set of double trailers, it is necessary to close shut-off valves on
some trailers. Where are these valves located?
A: in the front of trailers
B: in the middle
C: at the back of trailers used to tow other trailers - answer-at the back of trailers
used to tow other trailers
Before you back under a trailer, make sure of what?
A: the trailer brakes are locked
B: the air supply knob is in
C: the air brakes are off - answer-the trailer brakes are locked
To unlock the fifth wheel, you pull the handle to what position?
A: open
B: neutral
C: closed - answer-open
After connecting the air lines but before backing under the trailer, you should:
A: supply air to the trailer, then pull out the trailer air supply valve
B: make sure that the trailer brakes are off
C.: walk around the rig to be sure it is clear - answer-supply air to the trailer, then
pull out the trailer air supply valve
You are coupling a tractor to a semi-trailer and you have backed up but are not
yet under it. What should you hook up before backing under it?
A: the emergency and service air lines
