An unladen commercial combination vehicle is navigating a long mountain downgrade. Suddenly, the temperature drops and a sheet of black ice forms on the roadway. As the vehicle's speed marginally increases, the driver observes the rear of the tractor beginning to swing outward to the right, indicating a loss of drive-wheel traction. To immediately arrest this developing tractor jackknife and stabilize the vehicle, which specific course of action is required?
- Depress the clutch pedal immediately to disengage the drivetrain, ensure the service brakes are fully released, and swiftly turn the steering wheel to the right.Cevap
- BMaintain a steady throttle to pull the trailer forward, and turn the steering wheel sharply to the left to counteract the rightward movement of the tractor.
- CImmediately activate the auxiliary engine retarder to safely decelerate the drive wheels without risking pneumatic service brake lockup.
- DInitiate aggressive snub braking by locking the service brakes down to 5 mph below the target speed, forcing the drive tires to bite into the ice.
Cevap
Depress the clutch pedal immediately to disengage the drivetrain, ensure the service brakes are fully released, and swiftly turn the steering wheel to the right.
When the rear of the tractor swings to the right, it indicates a drive-wheel skid that will lead to a tractor jackknife if uncorrected. To recover, the driver must instantly stop whatever caused the skid by releasing the brakes and pushing in the clutch to eliminate all engine drag. Simultaneously, the driver must turn the steering wheel in the direction of the skid (to the right) to push the front of the vehicle back into alignment with the sliding rear.
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Drive-Wheel Skid Recovery and Tractor Jackknife Prevention