5.6.1 Thinking & Braking Distances

• What are the critical concepts in understanding the total stopping distance of a vehicle?

  Thinking and braking distances
• What is thinking distance?


  • Distance a vehicle travels from hazard perception to brake application
  • Influenced by driver's reaction time
• What is braking distance?

  • Distance a vehicle travels from brake application to complete stop
  • Depends on vehicle's speed, road conditions, and braking efficiency
• How is total stopping distance calculated?

  Total stopping distance is the sum of thinking distance and braking distance
• What is the formula for total stopping distance?

  Total Stopping Distance = Thinking Distance + Braking Distance
• What factors affect thinking distance?

  • Reaction time (average 0.75 seconds)
  • Speed (increases with speed)
  • Driver condition (tiredness, alcohol, drugs)
• What is the average reaction time for a driver?

  Approximately 0.75 seconds
• How does speed affect thinking distance?

  Thinking distance increases with speed
• What factors affect braking distance?

  • Speed (increases with the square of speed)
  • Road conditions (wet, icy, slippery)
  • Vehicle condition (worn-out brakes, tires)
  • Load and weight (heavier vehicles require longer distance)
• How does speed affect braking distance?

  Braking distance increases with the square of the vehicle's speed
• What happens to braking distance if the speed of the vehicle doubles?

  Braking distance increases by a factor of four
• What is the relationship between road conditions and braking distance?

  Poor road conditions increase braking distance due to reduced friction
• How does vehicle condition affect braking distance?

  Poor vehicle condition increases braking distance
• How does load and weight affect braking distance?

  Heavier vehicles require a longer braking distance to stop
• What is the formula to calculate thinking distance?

  Thinking Distance = Speed × Reaction Time
• If a vehicle is traveling at 20 m/s and the reaction time is 1 second, what is the thinking distance?

  20 meters
• What is the formula for braking distance?

  Braking Distance ∝ Speed²
• What does it mean that braking distance is proportional to speed squared?

  It means that if speed increases, braking distance increases quadratically
• What is the more precise formula for calculating braking distance considering friction and deceleration?

  Braking Distance = v² / (2 × a)
• What are the practical examples of calculating thinking and braking distances?

  Example 1:

  • Speed: 30 m/s, Reaction Time: 1 second
  • Thinking Distance: 30 meters
  • Braking Distance: 45 meters
  • Total Stopping Distance: 75 meters

  
  

  Example 2:

  • Speed doubles from 20 m/s to 40 m/s
  • Initial Braking Distance at 20 m/s: 20 meters
  • Braking Distance at 40 m/s: 80 meters
• What is summarized about thinking distance, braking distance, and total stopping distance?

  • Thinking Distance: Increases with speed and impaired reaction time
  • Braking Distance: Increases with speed, affected by road and vehicle conditions
  • Total Stopping Distance: Sum of thinking and braking distances; crucial for safe driving
• Why is understanding thinking and braking distances important for drivers?

  It helps drivers assess safe following distances and react appropriately to hazards