Let's put things into perspective here. There are some people who think it's "staged" and that the crash didnt look that bad. I'm not a physics expert or a science expert but I'll put it into my own words.
Well they're wrong. For one thing, NASCAR is far from being WWF or whatever the hell it's called. For another thing, If you look at the impacts of Dale Earnhardt, when Dale Earnhardt hit the wall at Daytona, he was going about speeds in excess of 185-195 miles per hour. Now when he hit the wall, that motion, that energy that the car had comes to a sudden halt and the fact that he's going a lot faster then other guys who hit the wall at like 120 or 130, then that force when it impacts, it's going to hurt, no not only hurt; it will kill. If NASCAR recorded the Gs (or amount of gravity I think) that Earnhardt's car absorbed when he got killed, then that G count will be very very high. After I've watched the 2001 Daytona 500 over and over again, Sure, Earnhardt's wreck didnt look that bad from the outside, but if you looked at it in a bit deeper perspective, then your opinion will change.
When Tony Stewart wrecked in the same race, the 2001 Daytona 500, his car was flipping over losing energy gradually and as the car hit the ground and came back into the air and vice versa, it was slowing down that and he didnt hit the wall all of a sudden.
When Jerry Nadeau hit the wall at Richmond, he was still accelerating and he was probably barreling off into the turn 1 at Richmond at 150 or 170 mph. Sure again, his wreck didnt look that bad. But he got injured pretty badly, enough for him to be in critical condition for a short while. Why? The G count, the forces his car absorbs when it hits the wall. The hit was probably bad enough to kill him but thankfully it didnt.
Now, when NASCAR measures Earnhardt Jr's wreck. There will be a High G count. Sure it didnt look bad from the outside, but all that energy and forward motion his car had entering turn 1 then it spun around and hit the wall at about 140, 150 then the Gs that his car absorbed. That's going to hurt, were it not for a lot of changes in the cars, then Jr. probably would be too injured to race. So, I'd be surprised if anyone still were to come up and say that the wreck was staged.