> However a car traveling at 200km/h has four times the kinetic energy as a car traveling at 100km/h so a collision at that speed is much less likely to be surv

> However a car traveling at 200km/h has four times the kinetic energy as a car traveling at 100km/h so a collision at that speed is much less likely to be survived than a collision at 100km/h. Kinetic energy by itself does not matter one bit when it comes to how damaging a crash will be for the human occupants. People use it as a proxy for acceleration and jerk. Kinetic energy is only actually useful when you're trying to figure out what acceleration and jerk will be if the crash involves multiple moving vehicles or hitting an object that's light enough to move. Imagine a freight train crashing into an immovable something at low speed. The kinetic energy is going to be higher than almost any car crash but the occupants will be just fine and they have far less crash protection stuff around them than anyone in a car. Alternatively, imagine an occupied small car traveling at some low speed crashing head on into a person who was shot out of a cannon at high enough speed for their kinetic energy to be equal. Both parties are going to decelerate over the same amount of time but the person shot out of the cannon will experience much higher acceleration (and jerk) because their initial velocity was higher.