Air Brake Driving Techniques & Vehicle Control Flashcards

What is 'jackknifing' and what is its primary cause?

Answer: The trailer swinging outward when drive or trailer wheels lock up during hard braking

Jackknifing occurs when the rear drive or trailer wheels lock, causing the trailer to swing out relative to the tractor.

When driving on slippery roads, how should you adjust your braking technique?

Answer: Begin braking earlier and apply lighter, more gradual pressure to avoid skidding

Gentle, early braking on slippery roads maintains tire traction and prevents wheel lockup or jackknife.

What is the correct response if your front wheels lock up during heavy braking?

Answer: Release some brake pressure to allow the front wheels to roll and restore steering

Locked front wheels eliminate steering control; releasing some pressure allows the wheels to roll and the driver to steer again.

How does improper cargo weight distribution affect air brake performance?

Answer: It changes weight transfer during braking, causing some axles to lock before others

Uneven load distribution alters how weight shifts during braking, potentially causing premature lockup on lightly loaded axles.

What is the primary function of an antilock braking system (ABS) on an air brake vehicle?

Answer: To automatically prevent wheel lockup, allowing the driver to steer while braking hard

ABS modulates brake pressure at each wheel to prevent lockup, preserving the driver's ability to steer during hard stops.

When braking with an ABS-equipped air brake vehicle, what is the correct driver technique?

Answer: Apply firm, steady brake pressure and steer normally — let ABS manage wheel speed

With ABS, the driver should maintain firm steady pedal pressure and steer as needed — the system automatically prevents wheel lockup.