By what factor does the braking distance increase when the speed of travel is doubled?

When a vehicle's speed is doubled, the kinetic energy involved in the motion increases significantly. Kinetic energy is proportional to the square of the speed, which means that if you double the speed, the kinetic energy increases by a factor of four (2^2 = 4).

Braking distance is directly related to the amount of kinetic energy that needs to be dissipated to stop the vehicle. Therefore, when speed is doubled, the distance required to come to a complete stop is quadrupled. This is why the correct response indicates that the braking distance increases by a factor of four when speed is doubled.

Understanding this principle is crucial for school bus drivers as it emphasizes the importance of maintaining safe speeds, especially in areas with potential hazards such as school zones, where stopping distances may be critical.