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District Of Columbia CDL Combination Test 2
Practice mode
Question
1
of 20
QUESTION 1 / 20
The trailer hand valve should:
Choose one answer below.
A
Be used for parking.
✓
B
Be used only to test the trailer brakes.
✓
C
Be used together with the brake pedal.
✓
D
Be used on slippery surfaces.
✓
QUESTION 2 / 20
Which of the following types of vehicles is most prone to the “crack-the-whip" effect?
Choose one answer below.
A
An automobile
✓
B
A three-axle tractor
✓
C
A bobtail tractor
✓
D
A triple combination
✓
QUESTION 3 / 20
Using the trailer hand brake while experiencing a trailer jackknife will:
Choose one answer below.
A
Stop the skid.
✓
B
Straighten the trailer.
✓
C
Increase traction.
✓
D
Continue the skid.
✓
QUESTION 4 / 20
Using the trailer hand valve while driving:
Choose one answer below.
A
Will help you turn safely.
✓
B
Will stop your trailer safely.
✓
C
Can cause a skid.
✓
D
Is impossible.
✓
QUESTION 5 / 20
Driving a combination vehicle ____ than driving a single vehicle.
Choose one answer below.
A
Is easier
✓
B
Requires more driving skill
✓
C
Is better for training
✓
D
Is safer in inclement weather
✓
QUESTION 6 / 20
Simply changing lanes can cause:
Choose one answer below.
A
A “crack-the-whip” effect, resulting in a rollover.
✓
B
A trailer to straighten out.
✓
C
Confusion over which lane the driver is hoping to use.
✓
D
Other drivers to reduce their speed.
✓
QUESTION 7 / 20
Avoid needing to make sudden lane changes by:
Choose one answer below.
A
Using your horn to encourage other drivers to move out of your lane.
✓
B
Only driving slower than the posted speed limit.
✓
C
Watching the road ahead while driving.
✓
D
Pulling off the road and waiting when there is high traffic.
✓
QUESTION 8 / 20
When uncoupling a trailer, landing gear should be:
Choose one answer below.
A
Raised completely.
✓
B
Lowered halfway.
✓
C
Just off the pavement.
✓
D
Firmly on the ground.
✓
QUESTION 9 / 20
If the trailer begins to skid, it is best to:
Choose one answer below.
A
Release the brakes.
✓
B
Accelerate.
✓
C
Quickly turn the steering wheel one way, then the other.
✓
D
Brake.
✓
QUESTION 10 / 20
If you need to back your trailer but cannot back up in a straight path, you should:
Choose one answer below.
A
Back toward the passenger's side.
✓
B
Back toward the driver's side.
✓
C
Swerve back and forth while backing.
✓
D
Always turn to your right.
✓
QUESTION 11 / 20
If your trailer begins to drift off course while you are backing, you should:
Choose one answer below.
A
Continue trying to back up without stopping.
✓
B
Turn the top of your steering wheel in the direction of the drift.
✓
C
Turn the top of the steering wheel in the direction opposite of the drift.
✓
D
Return the steering wheel to the 12 o’clock position.
✓
QUESTION 12 / 20
Rollovers happen when:
Choose one answer below.
A
A truck driver is driving too fast.
✓
B
The driver of a vehicle in front of a truck is moving to slowly.
✓
C
A truck driver is driving too slowly.
✓
D
ABS is working effectively.
✓
QUESTION 13 / 20
What is another name for the service line?
Choose one answer below.
A
The signal line
✓
B
The cable line
✓
C
The surplus line
✓
D
The power line
✓
QUESTION 14 / 20
How many air lines does a combination vehicle have?
Choose one answer below.
A
One
✓
B
Two
✓
C
Three
✓
D
Four
✓
QUESTION 15 / 20
If unsure if a trailer is equipped with ABS, you can:
Choose one answer below.
A
Check under the trailer for wheel speed sensors coming from the back of the brakes.
✓
B
Try driving on a slippery surface and see if ABS kicks in.
✓
C
Assume it does have ABS.
✓
D
Remove a tire and look for the ABS sensor on the axle.
✓
QUESTION 16 / 20
If a trailer begins to skid, the driver should:
Choose one answer below.
A
Lock the brakes.
✓
B
Release the brakes.
✓
C
Steer in the opposite direction.
✓
D
Accelerate.
✓
QUESTION 17 / 20
Rollovers are most likely to happen when:
Choose one answer below.
A
Drivers turn too fast.
✓
B
Driver turn too slowly.
✓
C
It is windy.
✓
D
It is raining.
✓
QUESTION 18 / 20
While inspecting a coupling, you should go under the trailer and:
Choose one answer below.
A
Detach the jaws from around the kingpin.
✓
B
Make sure the locking lever is in the "emergency" position.
✓
C
Remove the safety latch.
✓
D
Look into the back of the fifth wheel.
✓
QUESTION 19 / 20
When driving a tractor-trailer equipped with ABS, you should:
Choose one answer below.
A
Stop harder than you would otherwise.
✓
B
Use extra braking force to ensure the ABS kicks in.
✓
C
Brake as you normally would.
✓
D
Brake using less pressure than you would otherwise use.
✓
QUESTION 20 / 20
In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when:
Choose one answer below.
A
Air pressure drops to a level between 20 and 45 psi.
✓
B
You are experiencing a trailer jackknife.
✓
C
Wheels have regained traction after a skid.
✓
D
Air pressure is above 45 psi.
✓
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