Commercial Driving Vehicle Operation

Question 1

What is the correct technique for downhill braking with a commercial vehicle?

Accepted Answer

Use a low gear and apply brakes in short intervals to keep speed safe

Answer

Using engine braking in a lower gear combined with intermittent brake application prevents brake fade from overheating, which is the leading cause of loss-of-control on downgrades.

Question 2

What is the recommended following distance for a commercial vehicle at highway speeds?

Accepted Answer

6-7 seconds or more

Answer

Commercial vehicles require significantly more stopping distance than passenger cars. A minimum following distance of 6-7 seconds is recommended at highway speeds.

Question 3

What is the 'stab braking' technique?

Accepted Answer

Applying brakes fully, releasing when wheels lock, then reapplying when wheels start rolling again

Answer

Stab braking involves full brake application until wheels approach lockup, then releasing and reapplying. This is used in vehicles without anti-lock brakes during emergency stops.

Question 4

What causes a jackknife in a tractor-trailer?

Accepted Answer

The drive wheels losing traction while the trailer pushes the tractor, causing it to swing around

Answer

Jackknifing occurs when the drive wheels lock or lose traction, and the momentum of the heavy trailer pushes the tractor sideways, creating a V-shape between tractor and trailer.

Question 5

What is the proper procedure for entering a curve with a commercial vehicle?

Accepted Answer

Slow down BEFORE the curve and accelerate slightly through it

Answer

Reducing speed before the curve prevents rollover risk from centrifugal force. Gentle acceleration through the curve helps maintain vehicle stability and traction.

Commercial Driving Practice Test

Commercial Driving Practice Test

Commercial Driving Vehicle Operation