Approximately, by how much does the braking distance increase if speed is doubled?

Braking distance increases proportionally to the square of the speed, which follows from the laws of physics regarding kinetic energy. Therefore, a doubling of speed results in approximately a fourfold increase in braking distance (2 to the power of 2 is 4). This is especially dangerous in the conditions shown in the photo, where a wet road surface covered with mud and leaves drastically reduces tire grip further.