I am almost positive I heard David Crabtree on WRAL say tht it is against the law in NC to leave the scene of an accident; that would explain why some of the stories said that the State Patrol was talking to Brian Ross, the driver, but he would not be charged with leaving the scene.
I just can't find a link. :-)
This is the closest thing I've been able to find so far.
http://www.deadlyroads.com/laws/north-carolina-hit-and-run-laws.shtml
Wouldn't that depend on whether you caused the accident or just saw the accident?
Obviously, if someone caused it by sideswiping another car, they're probably not going to admit it - but they wouldn't be totally evil if they also called 9-1-1 after doing it.
Sounded to me like the other driver was just an observer - but he does need to provide eyewitness details if he can. Seems he has done so, voluntarily, so can't be forced by LE to do much more than that, legally.
It's hard to believe he's the only witness - and if he were part of the cause, there might be other witnesses to that who don't want to get involved.