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Difficulty: EasyRetarders Usage and Cautions

When driving on wet, icy, or snow-covered road surfaces, why should a commercial motor vehicle driver turn off the retarder?

  1. A
    The retarder causes excessive heat buildup and accelerates wear on the service brake linings.
  2. The braking force applied to the drive wheels can cause them to lose traction and start a skid.Answer
  3. C
    The retarder overloads the vehicle's electrical charging system when operating in cold temperatures.
  4. D
    The retarder locks the front steer axle wheels and prevents directional steering control.

Answer

The braking force applied to the drive wheels can cause them to lose traction and start a skid.
Retarders apply auxiliary braking power to the drive wheels whenever the accelerator is released. When tire traction is compromised by rain, ice, or snow, this additional drag on the drive wheels can cause them to lose grip and initiate a severe skid or jackknife. Drivers must switch off retarders in poor weather conditions.

Step-by-Step Solution

1
Identify the mechanism of retarder operation and which wheels receive braking force.
Retarders apply supplementary braking force directly to the drive wheels whenever the driver releases the accelerator.
Understanding where deceleration force is concentrated is essential for assessing vehicle stability.
2
Evaluate the effect of auxiliary drive-wheel braking on slick road surfaces.
On wet, icy, or snow-covered surfaces, tire grip is significantly reduced, so extra braking force on the drive wheels easily breaks traction.
When drive wheels lock or lose grip due to retarder torque on slippery roads, the vehicle can instantly skid or jackknife.

Key Concept

Retarders apply braking force to the drive wheels and must be turned off on slippery surfaces (wet, ice, snow) to prevent drive-wheel skids.
Estimated Time:45s
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Topics

Retarders Usage and Cautions

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