Seriously. It seems like a lot of folks here are conflicted by this one, or at least have to caveat their support. It sounds like someone got a wakeup call. Hopefully he will heed it.
When I was a brain-dead youth, it never occurred to me to throw rocks at cars BUT my farm buds and I used to play an even more dangerous game. We'd sneak out late at night with a million candle-power spotlight and set up to the side of a blind curve or hilltop crossroads. When a car would come we'd pop up from cover and spot the driver right in the eyes. We had a good laugh when they'd scream and cuss and swerve all over the place. Then we'd move to a different spot and do it again.
By grace of God alone, none of our victims wrecked out. There were a couple near-misses, though.
This got to be a habit with us. So much so that we went out one night after a blizzard. The road was down to one lane. The first guy we "zapped" ran off into a snowbank. We thought it was great fun until he popped out with a rifle and drew down on us. We ditched the light and took off running like mad. I don't know if he fired (he was surely blind as a bat at that moment anyway). We were crashing through brush and making a massive racket. We broke into an open field and kept running. In our haste we forgot there was a fence ahead and we both hit it running flat-out. The next day we had a lot of 'splaining to do: what happened to dad's light and why were we both limping and what the heck gave us those cuts and bruises?? I don't recall the cock-and-bull story we spun, but we NEVER even discussed doing that stunt again. Looking back, I think we got off really light.
There is room for conflict.
On the one hand, this is a deadly assault.
On the other, once you stop your car, it is unlikely the perp can lob another one far enough, and any follow up assault is likely not to constitute deadly force. So the threat is essentially over.
This makes firing at them, or running up the hill and beating the snot out of them more like retaliation than defense. Now, the latter needs to occur, to keep them from assaulting someone else, and in some states, you are justified in using deadly force to prevent a felony or defend someone else from using deadly force - but it would be a hard argument unless you can show that you waited for them to try to drop it on someone else before dropping them.
Now shooting from a bridge is another story altogether.