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Difficulty: MediumStopping and Braking Procedures

Because auxiliary braking retarders deliver additional stopping force exclusively through the drive axles, an operator must turn them off when traveling on wet, icy, or snow-covered surfaces to prevent drive-wheel skids.

Answer: Answer

Answer

True
Auxiliary retarders apply supplemental retarding force directly to the drive axles. On slippery or low-adhesion surfaces such as wet, snowy, or icy pavement, this localized drag can cause the drive tires to break traction and skid, potentially leading to a drive-wheel jackknife. Therefore, CDL safe vehicle operating procedures mandate turning off retarders under these conditions.

Step-by-Step Solution

1
Identify the mechanism and axle distribution of auxiliary braking retarders.
Auxiliary retarders supply retarding torque exclusively to the drive wheels rather than distributing braking force across all steer and trailer axles.
Understanding where deceleration forces are applied is critical for evaluating tire-to-road tractive limits.
2
Analyze tire traction dynamics on reduced-friction road surfaces.
Wet, snowy, or icy surfaces dramatically decrease the available coefficient of friction between the drive tires and the pavement.
When drive wheels experience retarding torque on low-friction pavement, the tires rapidly exceed their adhesion threshold.
3
Evaluate the safety protocol for auxiliary retarder management during slippery road operations.
Disabling the retarder prevents uncommanded drive-wheel lockup, preserving lateral stability and preventing jackknife events.
Commercial vehicle safety standards mandate disengaging auxiliary retarders whenever road traction is compromised.

Key Concept

Auxiliary Retarder Operating Constraints on Low-Traction Surfaces
Estimated Time:1m 0s
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Topics

Stopping and Braking Procedures

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