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Difficulty: MediumSkidding Causes and Correction

You are approaching a sharp bend on a wet road. Why is it important to complete all necessary braking before you start turning the steering wheel?

  1. A
    Applying the footbrake whilst turning causes the anti-lock braking system (ABS) to automatically disengage.
  2. Demanding both braking and steering forces simultaneously increases the risk of the tyres losing grip and skidding.Answer
  3. C
    Tyre tread grooves can only disperse surface water effectively when travelling in a straight line.
  4. D
    Braking into a bend causes the vehicle's overall stopping distance to double immediately.

Answer

Demanding both braking and steering forces simultaneously increases the risk of the tyres losing grip and skidding.
Tyres have a finite amount of grip available to transfer forces between the car and the road surface. In wet conditions, the total available grip is reduced. If you attempt to brake heavily and steer at the same time, the combined lateral and longitudinal forces can easily overwhelm tyre adhesion, causing the vehicle to slide. Completing all necessary braking in a straight line before turning ensures that full grip is available to steer smoothly and safely around the bend.

Step-by-Step Solution

1
Evaluate the tyre grip demands of individual vehicle control inputs.
Identify that tyres share available friction between longitudinal forces (braking or accelerating) and lateral forces (steering).
Tyres have a finite adhesion envelope that is significantly reduced on wet road surfaces.
2
Sequence the braking and steering actions before negotiating the bend.
Brake smoothly in a straight line to achieve a safe cornering speed before applying steering input.
Separating braking from steering reserves maximum grip for directional control, preventing wheel lock-up and skids.

Key Concept

Tyre Grip Allocation and Skid Prevention on Bends
Estimated Time:1m 0s
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Topics

Skidding Causes and Correction

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