I don't swallow it. I am saying that it's plausible. I've done that, and probably most of us here have.
Or maybe at the opposite extreme some testosterone-soaked junior lord of the universe was going down the road figuratively waving his thingus in everybody's face. Well? That doesn't justify following him home screaming at him and then hitting him with your car, especially if you yourself are a grown man and therefore theoretically supposed to (a) have some dimming memory of what being 17 was like and (b) more generally some skills at rising above rather than actively worsening life's petty aggravations.
The thing to keep in mind is that either interpretation of that original incident, and in fact most of the evolution, is at this point the story from one side or the other. In this and most other details (some of them important), we don't have the whole story. We don't even have the Cliff's Notes yet. We've got a couple of blurbs from the dust jacket.
Probably, as they say, it takes two to tango. Practical details are left as an exercise for the detectives and jury.
Now a man is dead and a 17-year-old is going to need one fast-talking laywer to get out of serving serious time. I don't see a win for anybody in this, and the only sure lesson to be learned is one we already knew, which is that hot-reactor personalities and the petty aggravations of driving can be a volatile combination.
Cheers, --Joe