CLP Basic Vehicle Control 2 — Questions and Answers
Question 1: When backing a commercial vehicle, you should primarily steer using which technique?
- Steer opposite to trailer movement (Correct answer)
- Use only mirrors without turning your body
- Get out and walk the path first, then back slowly
- Steer in the same direction you want the rear to go
Correct answer: Steer opposite to trailer movement
When backing, you steer the front of the tractor opposite to the direction you want the trailer to move.
Question 2: What is the correct way to use the clutch when starting a large commercial vehicle on a flat road?
- Release it quickly to avoid stalling
- Slip it slightly while applying moderate throttle (Correct answer)
- Hold it fully engaged until the engine revs high
- Press it to the floor and then release all at once
Correct answer: Slip it slightly while applying moderate throttle
Slipping the clutch slightly while applying moderate throttle allows a smooth start without stalling or jerking.
Question 3: When driving a commercial vehicle, what is the primary purpose of the trailer brake hand valve (trolley valve)?
- To slow the vehicle during normal highway driving
- To test trailer brakes and assist with parking (Correct answer)
- To apply emergency stopping force on all axles
- To independently control each trailer wheel
Correct answer: To test trailer brakes and assist with parking
The trailer brake hand valve is used to test trailer brakes and to help control trailer sway, not for normal driving stops.
Question 4: Which gear should a driver use when going down a long, steep grade?
- A gear higher than used to climb the same grade
- The highest gear available to maintain speed
- A low gear that keeps engine speed in a safe range (Correct answer)
- Neutral to allow engine braking to take effect
Correct answer: A low gear that keeps engine speed in a safe range
You should select a low gear before starting downhill so engine braking helps control speed without overheating the brakes.
Question 5: What does it mean when the low air pressure warning device activates in a commercial vehicle?
- The air compressor is working too hard
- Air pressure has dropped below a safe level (typically 60 psi) (Correct answer)
- A tire has lost pressure and needs inflation
- The parking brakes have been fully released
Correct answer: Air pressure has dropped below a safe level (typically 60 psi)
The low air pressure warning activates when system pressure falls to around 60 psi, signaling you must stop safely and address the problem.
Question 6: When making a right turn in a large commercial vehicle, why should you position the truck slightly left before turning?
- To give other drivers a warning that you are turning
- To allow the rear wheels enough room to complete the turn without hitting the curb (Correct answer)
- To check for traffic in the left lane before the turn
- To meet the minimum turning radius required by federal law
Correct answer: To allow the rear wheels enough room to complete the turn without hitting the curb
Off-tracking causes rear wheels to follow a shorter path than the front, so swinging left provides clearance for the trailer's rear axle.
Question 7: What is 'off-tracking' in commercial vehicle operation?
- When a trailer slides sideways on ice
- When the rear wheels follow a different, shorter path than the front wheels on a curve (Correct answer)
- When GPS navigation sends a driver off the planned route
- When the front axle loses traction during a turn
Correct answer: When the rear wheels follow a different, shorter path than the front wheels on a curve
Off-tracking occurs when rear wheels of a long vehicle cut inside the path of the front wheels on turns, creating a risk of running over curbs or pedestrians.
CLP Basic Vehicle Control 2
When backing a commercial vehicle, you should primarily steer using which technique?