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Difficulty: HardRetarders Usage and Cautions

When operating on wet, icy, or snow-covered roadways, switching an auxiliary retarder to its lowest active power setting provides safe supplemental deceleration while preventing drive-wheel skids.

Answer: Answer

Answer

False. Retarders must always be turned completely off on wet, icy, or snow-covered surfaces.
The statement is false because commercial driving safety rules require the retarder to be turned completely off whenever roads are wet, icy, or snow-covered. Retarding force applies only to the drive axle, and even low-level retarding torque upon accelerator release can overcome diminished tire traction, causing the drive wheels to lose grip and initiate a jackknife.

Step-by-Step Solution

1
Analyze the mechanical operation of auxiliary retarders and where their retarding force is applied.
Retarders apply supplemental braking torque exclusively to the drive wheels whenever the accelerator pedal is released.
Understanding the drive-axle concentration of retarding force explains why traction limits are easily exceeded on low-friction surfaces.
2
Evaluate the regulatory and safety rules regarding retarder settings in adverse weather conditions.
CDL safety guidelines state that retarders must be turned completely off whenever the road is wet, icy, or snow-covered, with no exceptions for low power settings.
Even reduced retarding power can overcome reduced tire traction when empty or lightly loaded, resulting in an unrecoverable drive-wheel skid.
3
Determine the validity of the statement.
The claim that using the lowest active setting is acceptable on slippery roads is incorrect.
The mandatory safety procedure requires complete deactivation of the retarder system.

Key Concept

Retarders must be completely disengaged on slippery surfaces because applying braking torque solely to the drive wheels can precipitate a drive-wheel skid or jackknife.
Estimated Time:1m 0s
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Retarders Usage and Cautions

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