CDL - COMBINATION VEHICLE FULL PRACTICE TEST STUDY GUIDE – WELL SOLVED
Q&A GRADED A+
You are uncoupling a trailer. After you shut off the trailer air supply and lock the trailer
brakes, you should
1. immediately apply your tractor parking brakes
2. begin to lower the trailer landing gear
3. back up gently and ease pressure on the fifth wheel locking jaws
back up gently to ease pressure on the fifth wheel locking jaws
When should you use the hand valve to park a combination vehicle?
1. To park at loading docks
2. To park on a grade
3. never
Never
The front trailer supports are up, and the trailer is resting on the tractor. Make sure that
1. there is enough clearance between the upper and lower fifth wheel
2. there is enough clearance between the tractor frame and the landing gear
3. the safety latch is in the unlocked position
there is enough clearance between the tractor frame and the landing gear
The trailer hand valve works the trailer brakes. Which of these statements is true?
1. the foot brake sends air to all the brakes on the vehicle ( including the trailer(s))
,2. The trailer hand valve should be used only to test the trailer brakes
3. all the above
all the above
Where should the tractor be when you inspect the landing gear after uncoupling the trailer?
1. With the fifth wheel directly beneath the kingpin
2. completely cleared from the trailer
3. with the tractor frame under the trailer
with the tractor frame under the trailer
After you lock the kingpin into the fifth wheel, you should check the connection by pulling
1. the tractor ahead gently with the trailer brakes locked
2. forward 50 feet, then turning right, and then left
3. the tractor ahead sharply to release the trailer brakes
the tractor ahead gently with the trailer brakes locked
At night, when a vehicle is carrying a load that extends four feet or more beyond the rear of
the body, there must be ________ at the extreme end of the load.
1. red lights
2. red flags
3. a red flag
red lights
, Which type of truck-trailer combination has the greatest chance of a "crack-the-whip"
rollover?
1. A tractor pulling three trailers
2. A single tractor trailer
3. A tractor pulling two trailers
A tractor pulling 3 trailers
Air and electrical lines from the tractor to the trailer should be...
1. pulled tight with very little slack
2. secured but with enough slack for turns
3. resting on the frame of the tractor.
secured but with enough slack for turns
Compared with a straight truck or bus, there are ________ things to inspect in combination
vehicles.
1. fewer
2. more
3. the same number of
more
What is the emergency air line for?
1. To engage the trailer brakes in case of air pressure loss
2. To have extra air pressure in case you need it
Q&A GRADED A+
You are uncoupling a trailer. After you shut off the trailer air supply and lock the trailer
brakes, you should
1. immediately apply your tractor parking brakes
2. begin to lower the trailer landing gear
3. back up gently and ease pressure on the fifth wheel locking jaws
back up gently to ease pressure on the fifth wheel locking jaws
When should you use the hand valve to park a combination vehicle?
1. To park at loading docks
2. To park on a grade
3. never
Never
The front trailer supports are up, and the trailer is resting on the tractor. Make sure that
1. there is enough clearance between the upper and lower fifth wheel
2. there is enough clearance between the tractor frame and the landing gear
3. the safety latch is in the unlocked position
there is enough clearance between the tractor frame and the landing gear
The trailer hand valve works the trailer brakes. Which of these statements is true?
1. the foot brake sends air to all the brakes on the vehicle ( including the trailer(s))
,2. The trailer hand valve should be used only to test the trailer brakes
3. all the above
all the above
Where should the tractor be when you inspect the landing gear after uncoupling the trailer?
1. With the fifth wheel directly beneath the kingpin
2. completely cleared from the trailer
3. with the tractor frame under the trailer
with the tractor frame under the trailer
After you lock the kingpin into the fifth wheel, you should check the connection by pulling
1. the tractor ahead gently with the trailer brakes locked
2. forward 50 feet, then turning right, and then left
3. the tractor ahead sharply to release the trailer brakes
the tractor ahead gently with the trailer brakes locked
At night, when a vehicle is carrying a load that extends four feet or more beyond the rear of
the body, there must be ________ at the extreme end of the load.
1. red lights
2. red flags
3. a red flag
red lights
, Which type of truck-trailer combination has the greatest chance of a "crack-the-whip"
rollover?
1. A tractor pulling three trailers
2. A single tractor trailer
3. A tractor pulling two trailers
A tractor pulling 3 trailers
Air and electrical lines from the tractor to the trailer should be...
1. pulled tight with very little slack
2. secured but with enough slack for turns
3. resting on the frame of the tractor.
secured but with enough slack for turns
Compared with a straight truck or bus, there are ________ things to inspect in combination
vehicles.
1. fewer
2. more
3. the same number of
more
What is the emergency air line for?
1. To engage the trailer brakes in case of air pressure loss
2. To have extra air pressure in case you need it
