Uncoupling Safely - ONLINE CDL SCHOOL

Practice free. No account needed.
Want your scores, test history, and progress in your driver dashboard? Create a free account or log in before starting to save your results.

Uncoupling Safely

Build confidence with 10 original questions about Uncoupling Safely. Review your answers and explanations after finishing.

Supplemental study practice. This is not a government licensing exam or ELDT certification, and does not replace hands-on training. Follow your state’s current handbook.

1 / 10

What is the correct way to disconnect the air lines when uncoupling a tractor-semitrailer?

Disconnect and place them on the ground

Disconnect and connect glad hands to dummy couplers or couple them together

Disconnect and tie them to the landing gear

Disconnect and leave them hanging

2 / 10

During uncoupling, why should you ease pressure on the fifth wheel locking jaws before pulling the release handle?

It makes it easier to release the locking lever

It keeps the landing gear from collapsing

It prevents air from leaking out of the system

It ensures the electrical lines disconnect smoothly

3 / 10

You are preparing to uncouple a loaded trailer. After the landing gear makes firm contact with the ground, what should you do next?

Turn the crank a few extra turns in low gear

Pull the tractor clear of the trailer

Disconnect the air lines immediately

Raise the landing gear completely off the ground

4 / 10

You are about to uncouple your tractor from a trailer. What should you check about the parking area before starting?

That the area is well lit

That the area is completely level

That the surface can support the weight of the trailer

That the area is free of any debris

5 / 10

After uncoupling and pulling the tractor completely clear of the trailer, what should you do before driving away?

Immediately accelerate away from the trailer

Check the area and make sure it is safe to proceed

Lower the landing gear further

Leave the parking brakes off

6 / 10

After disconnecting the electrical cable during uncoupling, how should you hang it?

Coiled around the landing gear

Left on the trailer

With the plug facing up for easy access

With the plug facing down to prevent moisture entry

7 / 10

Why should you keep your legs and feet clear of the rear tractor wheels when unlocking the fifth wheel?

To prevent damaging the tires

To keep from getting dirty

To maintain better balance

To avoid injury if the vehicle moves unexpectedly

8 / 10

While uncoupling, why is it important to chock the trailer wheels if the trailer does not have spring brakes?

To help the fifth wheel release more smoothly

To keep the landing gear from collapsing

To make it easier to disconnect the air lines

To prevent the trailer from moving if air leaks out

9 / 10

After unlocking the fifth wheel, why should you pull the tractor only partially clear of the trailer before stopping?

To make it easier to reconnect the air lines

To check the trailer lights

To prevent the trailer from falling if the landing gear collapses

To allow the trailer brakes to cool

10 / 10

When lowering the landing gear on an empty trailer during uncoupling, how far should you lower it?

Until it makes firm contact with the ground

Just enough to touch the surface lightly

Until the trailer is lifted off the fifth wheel

All the way to the bottom

Your score is

The average score is 0%

About the Uncoupling Safely practice quiz

This practice quiz focuses on Uncoupling Safely, listed under CDL Practice — Combination Vehicles. Use it to check what you understand, spot topics to revisit, and connect the material to safe, informed decisions on the road.

Before you begin

Keep your current CDL manual or course notes nearby. Read each prompt carefully and think through why an answer fits, especially when a question describes a vehicle, road, or workplace situation. Licensing rules and procedures can vary, so confirm requirements with current official materials for your state.

After you finish

Review any explanations shown with your results. Note unfamiliar terms or missed concepts, then revisit your manual or course notes before trying again. Use your score to guide study; understanding why an answer is correct matters more than the number alone.

Study note: These quizzes are independent study practice. They are not state licensing exams, official government materials, or ELDT certification, and they do not replace required training.

Explore CDL Tests to find more practice by subject.