A driver is navigating a fully loaded tractor-trailer combination down a steep, snow-packed mountain grade. Due to an overly aggressive brake application, the tractor's drive wheels lock up entirely. The rear of the tractor immediately breaks traction and begins swinging violently out to the left, initiating a jackknife. Arrange the following emergency recovery procedures in the exact chronological sequence required to arrest the skid and safely realign the vehicle.
- 1Instantly remove all pressure from the service brake pedal to allow the locked drive tires to unlock and regain rolling friction.
- 2Rapidly turn the steering wheel to the left, pointing the front tires directly into the path of the sliding rear.
- 3Monitor the tractor's alignment as traction is restored and the vehicle begins to swing back toward its intended path of travel.
- 4Execute a sharp counter-steer to the right at the precise moment the vehicle realigns to neutralize rotational momentum and prevent a secondary skid.
Answer
The correct sequence for recovering from a drive-wheel braking skid is to first release the service brakes entirely, quickly steer into the direction of the skid, wait for the vehicle to catch traction and begin realigning, and finally counter-steer to prevent an over-correction snap.
The established standard for recovering from a drive-wheel braking skid requires restoring rolling friction first by releasing the brakes. Once the wheels can roll, steering into the skid prevents the vehicle from folding. Waiting for the vehicle to realign before applying a precise counter-steer neutralizes the resulting rotational momentum, safely concluding the recovery.
Step-by-Step Solution
Key Concept
Drive-Wheel Braking Skid (Tractor Jackknife) Recovery Dynamics