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Difficulty: HardSkid Control and Recovery

A commercial motor vehicle driver negotiating a wet, curved interchange ramp notices the drive wheels losing traction and the rear of the tractor sliding outward. The driver correctly releases the accelerator and turns the steering wheel in the direction of the skid. As the vehicle begins to align and straighten out, what secondary action must the driver take to prevent skidding in the opposite direction?

  1. A
    Engage the engine retarder to maximum resistance to slow the spinning drive wheels down quickly.
  2. B
    Hold the steering wheel firmly in the direction of the initial slide until the combination comes to a complete halt.
  3. Counter-steer by turning the steering wheel in the opposite direction as soon as the vehicle starts to straighten.Answer
  4. D
    Apply firm, continuous service brake pedal pressure while steering toward the inside shoulder of the curve.

Answer

Counter-steer by turning the steering wheel in the opposite direction as soon as the vehicle starts to straighten.
During drive-wheel skid recovery, turning into the skid redirects the front of the vehicle along the slide path. However, as the vehicle starts to straighten out, the driver must immediately counter-steer in the opposite direction. Without this timely counter-steering, the vehicle's rear end will overshoot and skid violently in the opposite direction.

Step-by-Step Solution

1
Analyze the vehicle's dynamic state during the recovery sequence.
The initial turn into the skid has started to bring the vehicle back into alignment, but rotational momentum is carrying the rear axle past center.
When recovering from a drive-wheel skid, turning into the slide redirects the vehicle, but the inertia of the rear will cause an overshooting effect if steering input is maintained.
2
Identify the mandatory secondary steering input per commercial driving safety standards.
Execute a counter-steering maneuver by turning the wheel back toward the opposite direction.
Counter-steering stabilizes the chassis and prevents the vehicle from whipping around into a secondary skid or jackknife in the other direction.
3
Evaluate and reject improper auxiliary braking inputs.
Maintain rolling wheel traction without service braking or engine retarder activation.
Braking or engaging retarders on wet surfaces robs tires of cornering and rolling friction, causing total loss of directional control.

Key Concept

Drive-wheel skid recovery and secondary counter-steering technique
Estimated Time:1m 30s
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Topics

Skid Control and Recovery

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