Braking Distance

Key Stage 4

Braking distance is the distance a vehicle travels from the moment the brakes are applied to the moment the vehicle stops.

Braking distance makes up one of two parts of the stopping distance of a vehicle.

Braking distance depends on:

The speed of the vehicle - The greater the speed the larger the braking distance.
The conditions of the road and tyres - The less friction between the road and tyres the longer the braking distance. Water, oil or ice on the road all reduce the friction between the tyres and the road, causing the braking distance to be greater than for a dry road. Different road surfaces have different amounts of friction. The painted lines on the road and the metal of a manhole cover are both low friction surfaces which are especially dangerous for motorcycles which only have two wheels (at least with 4 wheels a car will have 3 of them on the normal road with 1 on the slippery surface of a line or manhole cover).
The condition of the brakes, if they are in poor condition there will not be enough friction.
The mass of the car. The more mass a car has the more force is required to slow it down so brakes providing a constant force won't be as effective. Higher: See Inertial Mass.
Weather conditions - Ice reduces friction with the road making braking distance longer.