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Difficulty: MediumDriving in Fog

Atmospheric moisture from dense fog rapidly creates a thin layer of slippery condensation on the road surface, requiring drivers to engage auxiliary engine retarders at maximum strength to maintain adequate braking efficiency.

Answer: Answer

Answer

False
The statement is false because condensation from fog makes asphalt slick. Commercial motor vehicle operators must turn off or disengage auxiliary engine retarders on wet or slippery surfaces because retarders apply retarding force only to the drive axle, creating a high risk of drive-wheel skidding and jackknifing.

Step-by-Step Solution

1
Assess the effect of dense fog on road surface conditions
Dense fog deposits atmospheric moisture, creating a slick layer of condensation on the pavement.
Moisture accumulation significantly reduces tire-to-pavement friction.
2
Examine the mechanical operation of auxiliary engine retarders
Engine retarders apply retarding force only to the drive axle rather than distributing braking across all wheels.
Retarder drag is concentrated exclusively on the drive tires.
3
Evaluate the safety hazard of using retarders on moisture-slicked roads
Applying retarders on slippery surfaces can lock up the drive wheels, leading to immediate loss of directional control and jackknifing.
CDL safety regulations mandate disengaging or switching off retarders whenever road conditions are wet, icy, or slick.

Key Concept

Disengaging auxiliary retarders on wet or moisture-slicked pavement during fog to prevent drive-wheel skidding and jackknifing
Estimated Time:1m 0s
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Topics

Driving in Fog

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