First of all, my heartfelt condolences to Kevin Ward's family- what an awful tragedy.
So first let me say that prior to this, Tony Stewart was my favorite driver in NASCAR...but I've watched that video a number of times, and to me, there is absolutely no doubt that he's at fault, and it's appalling to me that I haven't heard of any criminal charges being directed toward him yet.
To those saying 'well Kevin Ward shouldn't have ran out on the racetrack', let me make two things clear:
1. Shortly after Ward crashed, the race was under caution. No racing is taking place at that time, and all drivers should be exercising care while driving past the incident the same way any sensible everyday driver would when driving through road construction or a recent wreck. This is something that shouldn't even have to be explained to most people.
2. Running on the track during a caution period and gesturing unhappiness toward another driver immediately after crashing is nothing new- racers do it ALL the time. Hell, Tony Stewart himself has done it at least a few times that I know of.
For those who can stomach the video again, notice the blue and white car that passed Ward just before Stewart- he was at the very bottom of the track. This is exactly where Stewart should have been, NOT accelerating up the track and close enough to allow something like this to happen!
A lot of people are trying to figure out whether it was his intention to do hit him or not, but that is irrelevant at this point- based on his speed, position on the track, and the fact you can clearly hear his car revving up, Tony was not exercising the caution he should've been, and he killed a man as a result. A decent analogy for this is reaching for a cookie in the cookie jar, but instead the jar falls on the floor and breaks...who's fault is that?? Is the kid who reached for it completely exempt of all punishment just because the outcome was different than he/she intended it to be? Of course not!!
My best guess is Tony was upset too (he's without question a hothead, one of the biggest in ALL of racing), intended to intimidate the kid and screwed up. It's an accident that absolutely could've been avoided, and that's why Tony should be in custody today.