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Question

Difficulty: MediumIce and Snow Conditions

You are driving along a level road covered in compacted snow and ice. Why should you drive at a slow speed in the highest practical gear?

  1. A
    It allows rapid acceleration if the vehicle begins to slide sideways
  2. It reduces engine torque delivered to the driven wheels, helping to prevent wheelspinAnswer
  3. C
    It enables you to depress the clutch pedal continuously so the vehicle can coast freely
  4. D
    It increases engine braking force to achieve normal dry-weather stopping distances

Answer

Driving in the highest practical gear reduces engine torque delivered to the driven wheels, helping to prevent wheelspin.
On ice and snow, tyre grip is minimal. Driving in the highest practical gear keeps engine revolutions low and dampens the torque delivered to the driving wheels. This smoother application of power helps prevent the wheels from spinning and losing traction.

Step-by-Step Solution

1
Identify the primary vehicle handling challenge when driving on icy or snow-covered surfaces
Tyre grip is severely compromised, meaning excess power sent to the driven wheels will easily break traction and induce wheelspin.
Compact snow and ice provide minimal friction between the tyres and the road surface.
2
Evaluate the mechanical effect of gear selection on wheel torque
Higher gears provide lower engine torque multiplication at the wheels compared to low gears.
Lower wheel torque allows gentler power delivery, making it easier to keep the tyres within their limited grip threshold.

Key Concept

Using a higher gear at low speeds reduces torque at the driven wheels to avoid wheelspin on slippery surfaces.
Estimated Time:1m 0s
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Topics

Ice and Snow Conditions

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