Stopping Distances

• Stopping Distance = Thinking Distance + Braking Distance
• Thinking Distance is how far the car travels during the driver’s reaction time (time between the driver seeing a hazard and applying the brakes)
• Braking Distance is the distance taken to stop under the braking force (once the brakes are applied)
• Thinking Distance is affected by:

  • Speed
  • Reaction Time
• Braking Distance is affected by:

  • Speed
  • Weather or Road Surface
  • Condition of your Tyres
  • How Good Your Brakes are
• When the brake pedal is pushed, this causes brake pads to be pressed onto the wheels. This contact causes friction which causes work to be done. The work done between the brakes and the wheels transfers energy from the kinetic energy stores of the wheels to the thermal energy stores of the brakes. The brakes increase in temperature
• The faster a vehicle is going, the more energy it has in its kinetic stores so the more work needs to be done to stop it. This means that a greater braking force is needed to make it stop within a certain distance
• A larger braking force means a larger deceleration. Very large decelerations can be dangerous because they may cause brakes to overheat or could cause the vehicle to skid