Vehicle Stopping Distance

What is the stopping distance?

The total distance travelled from when the driver first spots the obstruction to when the car stops.

What are the two parts of stopping distance?

• Think distance

• Braking distance

What is thinking distance?

The distance travelled by the car during the driver’s reaction time.

What is reaction time?

The time taken for the driver to spot the obstruction, make a decision and then move their foot to the brake.

What is the braking distance?

The distance the car travels from when the driver applies the brakes to when the car sto

What happens if a vehicle is travelling at a greater speed?

The stopping distance will be greater.

Greater speed of the vehicle, the greater the stopping distance (assuming same braking distance is applied)

What are the typical reaction times for people?

Between 0.2s and 0.9s.

How can we measure reaction time?

• Using a ruler

• Volunteer places ruler next to their hand.

• They must catch it as it is dropped.

• The further the ruler falls before it is caught, the longer the reaction time.

What can affect reaction time?

• Tiredness will cause a longer reaction time.

• Alcohol and some drugs can make reaction time longer.

• Distractions in car e.g. mobile phone.

What factors can affect the braking distance?

• Wet or icy conditions reduce the friction between tyres and the road and increase braking distance.

• If a car has worn tyres, braking distance will increase. Also reduces friction.

• Worn brakes.