A commercial driver operating an articulated tractor-trailer on a snow-packed downgrade notices the drive wheels losing lateral grip and the rear of the tractor starting to rotate toward the right shoulder. Arrange the following emergency recovery actions in the correct chronological sequence to regain directional control and stabilize the combination vehicle.
- 1Release the accelerator and disengage any auxiliary driveline retarder to eliminate rotational drag and allow the drive wheels to roll freely.
- 2Turn the steering wheel toward the right (in the direction of the skid) to arrest the initial rotation of the tractor.
- 3Counter-steer promptly back to the left as the tractor begins to align, preventing an over-correction and secondary skid in the opposite direction.
- 4Maintain rolling tire friction without applying service brakes until the combination vehicle is fully tracking straight within the lane.
Answer
The correct sequence begins with releasing the throttle and disengaging any retarder drag, followed by steering in the direction of the skid, promptly counter-steering back to center as the vehicle responds, and finally maintaining rolling traction without braking until fully stabilized.
Safely recovering from a drive-wheel skid requires restoring rolling friction first by eliminating drive axle drag (releasing throttle and retarder), steering in the direction of the skid to stop rotation, immediately counter-steering in the opposite direction as the vehicle aligns to prevent a secondary skid, and allowing the unit to stabilize without touching the service brakes.
Step-by-Step Solution
Key Concept
Drive-wheel skid recovery and secondary counter-steering technique for commercial articulated vehicles
Estimated Time:1m 30s