CDL Doubles Triples Practice Test 1

Question 1

What is rearward amplification?

Accepted Answer

'Crack-the-whip' effect when making quick lane changes

Answer

Weight transfer to the rear axles when going up a hill in a double/triple

Answer

The increased weight on the rear axles of a double or triple trailer

Answer

Sudden, dangerous weight shift from the front to the rear trailer

Question 2

In a set of triples, where should the heaviest trailer be?

Accepted Answer

First trailer position (behind the tractor)

Answer

Second trailer position

Answer

Third trailer position

Answer

Either second or third trailer position

Question 3

Why should you never disconnect the pintle hook with the dolly still under the rear trailer?

Accepted Answer

The dolly tow bar may fly up, possibly causing injury

Answer

The kingpin may become damaged

Answer

The pintle lock mechanism may become damaged

Answer

The emergency brake will activate

Question 4

When connecting the converter dolly to the front trailer, what do you do first?

Accepted Answer

Back first semitrailer in front of dolly tongue

Answer

Secure converter gear support in the upright position

Answer

Release dolly brakes

Answer

Lock pintle hook

Question 5

If a second trailer does not have spring brakes, how should you set the brakes when you are coupling?

Accepted Answer

Drive the tractor close to the trailer, connect the emergency line to charge the trailer air tank and disconnect the emergency line

Answer

Connect the service air line to the trailer and use the Johnson bar to work the trailer brakes.

Answer

Manually adjust the slack adjusters to move the brake shoes in contact with the trailer brake drums

Answer

Connect the service air line to the trailer and press down on the brake pedal while you connect the trailer

Question 6

Pushing in the trailer air supply knob will do what?

Accepted Answer

Supply air to the emergency air line

Answer

Supply air to the service air line

Answer

Shut off air to the trailer air tank

Answer

Put on the emergency brakes

Question 7

How should you check that you have sufficient emergency airflow to all trailers in a set of doubles or triples?

Accepted Answer

Push in the red trailer air supply knob, open the emergency line shut-off valve at the rear of the last trailer and listen for air escaping.

Answer

Use the trailer hand brake to supply air. Go to the rear of the last trailer, open the service line valve and listen for air escaping.

Answer

Move the trailers and apply the emergency brakes.

Answer

Fully charge the air system, activate the emergency brakes and look for a 15 psi air pressure reduction

Question 8

What is the main purpose of a trailer shut-off valve?

Accepted Answer

To close the air lines of the last trailer to prevent air from leaking out

Answer

It works the trailer brakes

Answer

To be used only for emergency stopping

Answer

A coupling device that connects the air lines between converter dollies and trailers

Question 9

What is the correct position of the shut-off valves for the last trailer of a doubles or triples set?

Accepted Answer

Fully closed

Answer

Fully open

Answer

Partially open

Answer

Emergency shut-off valve open; service shut-off valve closed

Question 10

What is the correct position of the shut-off valves for the first trailer of a doubles or triples set?

Accepted Answer

Fully open

Answer

Fully closed

Answer

Partially closed

Answer

Emergency shut-off valve closed; service shut-off valve open