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Difficulty: HardSkid Control and Recovery

A heavy commercial vehicle hauling freight on a wet highway experiences a drive-wheel skid where the rear of the vehicle steps out to the left. The driver immediately lets off the accelerator and turns quickly to the left to align with the direction of travel. What critical steering action must the driver execute immediately as the vehicle begins to straighten out?

  1. A
    Hold the steering wheel locked to the left until forward momentum ceases and traction is completely restored.
  2. Counter-steer by quickly turning the steering wheel back in the opposite direction to prevent a secondary skid.Answer
  3. C
    Switch the auxiliary engine retarder to maximum setting to increase axle drag and stabilize rear wheel rotation.
  4. D
    Apply firm, continuous service brake pressure while maintaining the left steering input to arrest momentum.

Answer

Counter-steer by quickly turning the steering wheel back in the opposite direction to prevent a secondary skid.
During a drive-wheel skid, once the vehicle starts coming back on course, rotational momentum causes it to continue turning past center. CDL guidelines require the driver to counter-steer immediately by turning the wheel quickly back the other way to prevent a secondary skid in the opposite direction.

Step-by-Step Solution

1
Analyze the vehicle state during the realignment phase of a drive-wheel skid recovery.
The driver has already addressed the initial skid by releasing the throttle and steering left into the skid direction.
Initial steering brings the rear drive axle back in line with the vehicle's direction of travel.
2
Determine the physical momentum and rotational inertia acting on the vehicle body as it straightens.
The vehicle develops rotational momentum that will cause it to overshoot the center line and whip around into an opposite-side skid if steering is held.
Commercial vehicles have high polar inertia, creating a secondary pendulum effect during skid correction.
3
Identify the mandatory secondary control technique defined in CDL safety procedures.
Rapid counter-steering back toward the right (opposite direction) to center the vehicle safely.
Counter-steering cancels rotational yaw rate before an opposite skid can develop.

Key Concept

Drive-Wheel Skid Recovery and Counter-Steering Dynamics
Estimated Time:1m 30s
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Topics

Skid Control and Recovery

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