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Difficulty: HardCoasting and Engine Braking

While approaching a sharp bend on a rural road, a driver depresses the clutch pedal and holds it down throughout the turn. What is the primary hazard associated with this driving habit?

  1. A
    It causes the fuel management system to flood the engine cylinders with unburnt fuel.
  2. B
    It cuts off electrical power to the vehicle's electronic stability and anti-lock braking systems.
  3. It removes engine braking resistance, reducing tyre grip balance and making steering control less predictable.Answer
  4. D
    It doubles the thinking distance by delaying the hydraulic engagement of the footbrake pedal.

Answer

It removes engine braking resistance, reducing tyre grip balance and making steering control less predictable.
Keeping the clutch pedal depressed (coasting) disconnects the engine from the transmission. This removes the steadying drag of engine braking, placing the entire burden of speed control on the footbrake, shifting tyre grip away from steering, and making the vehicle far less stable and responsive through a corner.

Step-by-Step Solution

1
Analyse the physical state of the vehicle when coasting into a bend.
Holding the clutch down disconnects the engine from the driven wheels, eliminating engine braking resistance.
Engine braking naturally helps regulate forward momentum and maintain balanced weight distribution over all four tyres.
2
Evaluate the effect of disengaged drivetrain on steering and cornering dynamics.
Without engine drag, the vehicle tends to carry more momentum into the turn, requiring heavier footbrake usage and reducing the lateral grip available for steering.
Tyres have a finite amount of adhesion shared between braking and cornering forces.
3
Determine the resulting hazard to safe vehicle control.
Steering responsiveness becomes less predictable and the vehicle is significantly harder to stabilise if road grip changes.
Maintaining the correct gear before entering the bend ensures optimal stability, precise steering feel, and immediate throttle responsiveness.

Key Concept

Impact of Coasting on Steering and Vehicle Stability
Estimated Time:1m 30s
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Topics

Coasting and Engine Braking

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