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Question

Difficulty: MediumAccelerating Methods

A commercial motor vehicle driver is accelerating away from an intersection on a rain-slicked roadway when the drive wheels begin to spin. In what sequence should the driver execute the following steps to regain traction and safely resume acceleration?

  1. 1Take foot off the accelerator pedal immediately to stop drive-wheel spin.
  2. 2Allow the drive wheels to slow down and re-establish rolling grip with the road surface.
  3. 3Reapply throttle very gradually to initiate smooth forward acceleration.
  4. 4Increase speed progressively while continually monitoring for drive-wheel slippage.

Answer

The correct procedural order is: (1) Take foot off the accelerator pedal immediately to stop drive-wheel spin, (2) Allow the drive wheels to slow down and re-establish rolling grip with the road surface, (3) Reapply throttle very gradually to initiate smooth forward acceleration, and (4) Increase speed progressively while continually monitoring for drive-wheel slippage.
According to commercial driving standards, if drive wheels begin to spin on poor-traction surfaces such as wet or icy pavement, the operator must immediately remove their foot from the accelerator. Once the spinning wheels slow down and re-establish rolling contact with the roadway surface, the driver can then reapply the throttle very gradually and accelerate smoothly up to road speed.

Step-by-Step Solution

1
Release the accelerator pedal immediately upon detecting drive-wheel spin.
Engine power to the drive axle drops, stopping the spinning drive wheels from spinning uncontrollably.
Continuing to apply throttle on slick pavement will only spin the wheels faster, worsening traction loss and risking directional instability.
2
Allow the driving tires to slow and synchronize with vehicle road speed.
Tires regain rolling contact with the wet pavement.
Static/rolling traction must be restored before the tires can effectively propel the vehicle.
3
Reapply the throttle pedal very gradually.
The commercial vehicle begins moving forward smoothly without breaking tire grip.
Gentle power delivery prevents sudden torque spikes that cause immediate re-spinning.
4
Build speed progressively while monitoring traction and tachometer feedback.
The vehicle safely reaches desired travel speed under poor traction conditions.
Ongoing speed and space management ensures the vehicle stays stable across variable pavement conditions.

Key Concept

Traction Recovery and Progressive Throttle Control on Low-Traction Surfaces
Estimated Time:1m 0s
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Topics

Accelerating Methods

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