More on Stopping Distance

The figure below for typical stopping distance are from the Highway Code
To avoid an accident, drivers need to leave enough space between their car and the one in front so that if they had to stop suddenly they would have time to do so safely. ‘Enough space’ means the stopping distance for whatever speed they’re going at
Speed limits are really important because speed affects the stopping distance so much

As a car speeds up, the thinking distance increases at the same rate as speed. The graph is linear
This is because the thinking time stays pretty high constant-but the higher the speed, the more distance you cover in that same time
Braking distance, however, increases faster the more you speed up,.The work done to stop the car is equal to the energy in the car’s kinetic energy store. So as speed doubles, the kinetic energy increase 4-fold, and so the work done to stop the car increases 4-fold. Since W=Fs and the braking force is constant the braking distance increases 4-fold.
Stopping distance is a combination of these two distances so the graph of speed against stopping distance for a car looks like this:
You need to be able to interpret graphs like this for a range of vehicles-they’re all a similar shape