SGI Heavy Commercial Vehicle Operations Flashcards

What is 'jackknifing' in a tractor-trailer combination?

Answer: The trailer swings out at an angle relative to the tractor during braking

Jackknifing occurs when excessive braking causes the trailer to swing outward, folding the combination like a closing jackknife.

What is the correct way to back a tractor-trailer to the left?

Answer: Turn the steering wheel to the right to move the trailer to the left

To back a trailer to the left, the driver turns the steering wheel to the right, which pushes the rear of the trailer to the left.

What is the 'off-tracking' phenomenon in large vehicles?

Answer: Rear wheels follow a shorter path than front wheels around curves

Off-tracking means the rear axles of a large vehicle track inside the path of the front wheels, requiring drivers to swing wider on turns to avoid hitting curbs.

What is the minimum depth allowed for tire tread on a commercial vehicle's front steering axle?

Answer: 4.8 mm (6/32 inch)

Front steering axle tires require a minimum of 4.8 mm (6/32 inch) of tread depth due to their critical role in vehicle control.

What should a commercial driver do when a tire blows out on a rear axle?

Answer: Hold the wheel firmly, gradually ease off the throttle, and steer straight to a safe stop

Holding the wheel firmly and gradually slowing down maintains control, as sudden braking can cause the vehicle to swerve or jackknife.

What does 'gross vehicle weight rating' (GVWR) mean?

Answer: The maximum operating weight of a fully loaded vehicle as specified by the manufacturer

GVWR is the maximum total weight of the vehicle including the vehicle itself, fuel, passengers, and cargo, as specified by the manufacturer.