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Difficulty: MediumSpeed and Road Conditions

On icy road surfaces, vehicle traction is substantially lower when the ambient temperature is near the freezing point (32∘F32^\circ\text{F}) than when it is well below zero (0∘F0^\circ\text{F}), requiring commercial motor vehicle operators to exercise even greater speed reduction.

Answer: Answer

Answer

True. Traction is significantly lower near 32∘F32^\circ\text{F} than at 0∘F0^\circ\text{F} because melting produces a slippery layer of liquid water on top of the ice.
The statement is correct because melting surface ice at or near 32∘F32^\circ\text{F} creates a layer of liquid water that acts as a lubricant, making wet ice significantly more hazardous and slippery than dry, solid ice at 0∘F0^\circ\text{F}.

Step-by-Step Solution

1
Evaluate the physical characteristics of ice at different ambient temperatures.
At temperatures around 32∘F32^\circ\text{F}, ambient warmth and tire friction cause the top layer of ice to melt into liquid water.
Understanding surface friction dynamics under varying temperature conditions is essential for commercial vehicle speed management.
2
Determine the impact of the liquid water film on tire-to-surface traction.
The thin water layer acts as a lubricant, making wet ice near 32∘F32^\circ\text{F} far more slippery than dry, solid ice at 0∘F0^\circ\text{F}.
Official commercial driving safety guidelines specify that warmer ice near the freezing point provides less traction and necessitates greater speed reduction to a crawl.

Key Concept

Effect of ambient temperature on icy road surface traction and required speed adjustment
Estimated Time:45s
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Topics

Speed and Road Conditions

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