MN CDL Combination Practice Test (2024)

1. What is the emergency air line for?

It controls the front brakes of the tractor in case of an emergency.
It tells you the amount of brake pressure you need to stop the vehicle.
It supplies air to the trailer air tanks, and controls the emergency brakes on combination vehicles.
All of the above.

2. To unlock the fifth wheel, pull the release handle to the _______ position.

3. After starting the engine, the ABS light stays on. This means:

the ABS oil level is not adequate.
the ABS is working properly.
the ABS is in Neutral.
the ABS is not working properly.

4. If your vehicle catches fire, you should pull over:

5. If a trailer does not have spring brakes, to keep the trailer from moving you should:

6. When you park trailers without spring brakes, you should use wheel chocks:

to prevent the transmission from shifting up.
to keep the trailer from moving.
to prevent air from escaping.
to prevent overheating.

7. Which of the following is not a reason for covering cargo?

To prevent other drivers from looking at the cargo
To protect the cargo from weather
To protect people from spilled cargo
All of the above.

8. The iron trailer supports are up, and the full weight of the trailer is resting on the tractor. Make sure:

you are in a low enough gear.
there is enough clearance between the upper and lower fifth wheel.
the safety latch is not engaged.
there is enough clearance between the rear of the tractor frame and the landing gear.

9. When connecting the glad hands, you should press the two seals together with the couplers at a ______ angle to each other.

10. When you turn suddenly while pulling doubles, which trailer is most likely to turn over?

The front trailer is twice as likely to turn over as the tractor.
The rear trailer is twice as likely to turn over as the tractor.
All trailers are equally likely to turn over.
None of the above.

Shakopee Public Schools