Rant: Shitty fucking dangerous drivers

[John V]

At a combined impact velocity of a hundred miles per hour

Opposing velocity vectors aren't additive like that. Two people going at 50 mph toward each other will experience a crash of 50 mph. This is proven by thinking of two situations:

1) two cars crashing at 50 mph
2) a car crashing into a sturdy wall at 50 mph

Both will result in that car being stationary after the crash. In the case of the wall, it means the wall supplied a force equal, but opposite, to the car's force, leaving it stationary. The wall wasn't moving though. Therefore, in the first example, the second car is acting like a stationary wall, thus meaning that the experienced force is that of 50 mph.

/physics

You're lucky you don't live in Australia. On a daily basis I see shocking drivers...

You're better off hitting a parked car than hitting the same car coming at you at 50mph. There's a lot more total energy to be absorbed.