SD CDL - South Dakota Commercial Drivers License Combination Vehicle Operations Questions and Answers

Question 1

You are driving a combination vehicle and make a sudden lane change. What is the 'crack-the-whip' effect?

Accepted Answer

The tendency of the rear trailer to swing out with greater force than the tractor.

Answer

The front of the tractor swinging wide in a turn.

Answer

A delayed braking response from the rearmost trailer.

Answer

A loud noise made by the air brakes when applied suddenly.

Question 2

When coupling a tractor to a semitrailer, what is the correct height for the trailer?

Accepted Answer

The trailer will be raised slightly when the tractor is backed under it.

Answer

The trailer should be about one foot lower than the fifth wheel.

Answer

The trailer should be high enough that the tractor has to be lowered to get under it.

Answer

The fifth wheel should make contact with the kingpin before it touches the trailer apron.

Question 3

Which of the following is a primary factor that contributes to the rollover risk of combination vehicles?

Accepted Answer

A high center of gravity.

Answer

Low tire pressure.

Answer

An empty trailer.

Answer

Newly paved road surfaces.

Question 4

A driver is operating a combination vehicle with a dual air brake system. With the engine off and the brakes released, what is the maximum allowable air pressure leakage rate per minute?

Accepted Answer

3 PSI

Answer

1 PSI

Answer

4 PSI

Answer

2 PSI

Question 5

While uncoupling a trailer, after you have lowered the landing gear and disconnected the air and electrical lines, what is the next step?

Accepted Answer

Unlock the fifth wheel by pulling the release handle.

Answer

Drive the tractor completely out from under the trailer.

Answer

Chock the trailer wheels.

Answer

Set the trailer brakes.

Question 6

Under what condition does a combination vehicle, particularly a tractor-trailer, take longer to stop?

Accepted Answer

When it is empty or lightly loaded.

Answer

When it is fully loaded.

Answer

When driving on a downhill grade.

Answer

When the road is wet.