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Difficulty: MediumRetarders Usage and Cautions

On steep mountain downgrades covered in packed snow or standing water, a driver should engage the engine retarder to reduce heat buildup in the foundation brakes.

Answer: Answer

Answer

False. Drivers must turn off retarders on wet, icy, or snow-covered surfaces because the retarding force applied to the drive wheels can trigger a loss of traction and cause a skid.
The statement is false because commercial vehicle safety regulations require retarders to be turned off whenever pavement friction is compromised by rain, snow, or ice. Because retarders apply braking action only to the drive wheels, their engagement on slippery downgrades can immediately cause the drive tires to lose traction and trigger a jackknife.

Step-by-Step Solution

1
Identify the primary operational rule for auxiliary retarders under adverse surface conditions.
Commercial driving safety regulations mandate turning off retarders whenever road surfaces are wet, icy, or snow-covered.
Retarders apply supplemental braking force to the drive axle only, which can break tire grip on low-friction pavement.
2
Evaluate the statement against the safety hazard of drive-wheel skids.
Even though retarders reduce foundation brake heat on dry downgrades, using them on packed snow or standing water creates an immediate risk of skidding and jackknifing.
Preventing a catastrophic drive-wheel skid takes priority over auxiliary brake cooling on slippery downgrades.

Key Concept

Retarder Deactivation on Slippery Roadways
Estimated Time:45s
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Topics

Retarders Usage and Cautions

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