How does braking distance change when increasing speed from 30 mph to 60 mph?

When the speed of a vehicle increases, the braking distance does not increase linearly; it is influenced by the square of the speed. This means that when you double the speed, the braking distance increases by a factor of four. In practical terms, if a car traveling at 30 mph requires a certain distance to come to a stop, when the speed increases to 60 mph, the braking distance will be four times greater than that required at 30 mph.

This relationship is based on the physics of motion, particularly the kinetic energy of the vehicle. Kinetic energy increases with the square of the speed, meaning that at higher speeds, much more energy needs to be dissipated through braking in order to bring the vehicle to a stop. This is why the correct answer indicates that the braking distance quadruples when speed is increased from 30 mph to 60 mph.