CDL Combination Vehicles Practice Test 1

Question 1

A fully loaded rig is _________ times more likely to roll over in a crash than an empty rig.

Accepted Answer

10

Answer

A fully loaded rig has a significantly higher center of gravity and much greater momentum compared to an empty one. This increased mass and higher center of gravity make it far more susceptible to rolling over during sudden maneuvers or impacts. Therefore, the risk of a rollover crash is drastically amplified when the vehicle is fully loaded.

Question 2

When following behind other vehicles, you should follow

Accepted Answer

At least one second for every 10 feet of your vehicle length, plus one second if going over 40 MPH

Answer

The 'one second for every 10 feet of vehicle length' rule provides a basic safe following distance. Adding an extra second when traveling over 40 MPH accounts for the increased stopping distance and reduced reaction time at higher speeds. This adjustment ensures adequate space to react and stop safely, especially with a large commercial vehicle.

Question 3

A trailer jackknife is likely to happen when

Accepted Answer

The wheels of the trailer lock up

Answer

A trailer jackknife occurs when the trailer pushes the tractor from behind, causing the trailer to swing out to the side. This typically happens when the trailer wheels lock up, losing traction and sliding, while the tractor continues to move forward. The locked trailer wheels act as a pivot point, leading to the dangerous jackknife angle.

Question 4

What is the fastest and best way to recognize that your trailer has started to skid?

Accepted Answer

Seeing it in your mirrors

Answer

The fastest and most reliable way to detect a trailer skid is by observing it in your mirrors. You will see the trailer begin to swing out of alignment with the tractor. Relying on feel or sound can be delayed or less distinct, making visual confirmation crucial for timely corrective action.

Question 5

If your trailer begins to skid, you should

Accepted Answer

Release your brakes until the trailer wheels grip the road again

Answer

If your trailer begins to skid, the most effective action is to release the brakes. This allows the trailer wheels to unlock and regain traction with the road surface. Once traction is restored, the trailer can straighten out, preventing a jackknife or further loss of control.

CDL Practice Test

CDL Practice Test

CDL Combination Vehicles Practice Test 1