OK CDL Combination Practice Test (2024)

1. _________ can make vehicle handling unsafe.

2. When you make a quick lane change, the crack-the-whip effect can turn the trailer over. The crack-the-whip effect is caused by:

3. To test the tractor-semitrailer connection for security:

check that the trailer is locked onto the tractor by pulling the tractor gently forward while the trailer brakes are still locked.
plug the electrical cord into the trailer and fasten the safety catch.
pull out the air supply knob.

4. Empty trucks require _____ stopping distances because empty vehicles have ______ traction.

5. 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

6. The service line:

carries air to the parking brake to control the trailer brakes.
carries air and is connected to relay valves which allow the trailer brakes to be applied more quickly.
carries power steering fluid to control the trailer brakes.

7. If the fifth-wheel locking lever is not locked after the jaws close around the kingpin:

the coupling is not right and you should not drive until you get it fixed.
the parking brakes are on and your vehicle is safe to drive.
the parking brakes are on and the wheels are chocked.

8. Banked curves:

9. After a tire has been changed, the driver should stop a short while later to:

check the tightness of the nuts.
deflate the tire to 10 psi.
decrease tire pressure.

10. Emergency brakes are:

CDL COMBINATION PRACTICE TEST (OK)