Vehicle stopping distance

• What is the stopping distance?

  The total distance travelled from when the driver sees the obstruction to when the car stops.
• What two parts make up the stopping distance?

  Thinking distance - The distance travelled by the car during the driver's reaction time. The reaction time is the time taken for the driver to spot the obstruction, make a decision and move their foot to the break.

  Braking distance - The distance the car travels from when the driver applies the breaks to when the car stops.
• What effect does speed have on the stopping distance?

  The greater the speed of the vehicle, the greater the stopping distance ( assuming the same braking force is applied).
• What is a common speed limit in the UK?

  30 mph and at this speed a typical car what take 23 m to stop (6 car lengths)
• What is the range of reaction time for people?

  0.2 s and 0.9 s
• What factors increase a persons reaction time?

  Old age, fatigue, distractions, alcohol/drugs. These factors all increase the thinking distance.
• What factors affect the braking distance?

  • Wet / icy conditions reduce friction between the tyres and the road, increasing the braking distance
  • Worn tyres reduce friction between the tyres and the road.
  • Worn brakes increase the braking distance