Stopping Distances — Thinking and Braking

This lesson covers stopping distances as required by AQA GCSE Combined Science Trilogy (8464), section 6.5.3. Stopping distance questions appear frequently in AQA exams and often carry 4–6 marks, so understanding the factors that affect thinking and braking distances is essential.

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What Is Stopping Distance?

$\text{Stopping distance} = \text{Thinking distance} + \text{Braking distance}$Stopping distance=Thinking distance+Braking distance

Term	Definition
Thinking distance	The distance the vehicle travels during the driver's reaction time (between seeing a hazard and pressing the brake)
Braking distance	The distance the vehicle travels after the brakes are applied until it comes to a complete stop
Stopping distance	The total distance from when the driver sees the hazard to when the vehicle stops

graph LR
    H["Hazard seen"] -->|"Thinking distance"| B["Brakes applied"]
    B -->|"Braking distance"| S["Vehicle stops"]
    H -.->|"Stopping distance = thinking + braking"| S

    style H fill:#e74c3c,color:#fff
    style B fill:#f39c12,color:#fff
    style S fill:#27ae60,color:#fff

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Thinking Distance