First, I'm SOOO glad the driver is ok, and walked away from this one! I agree that the more accidents we hear of (and they are bound to happen) the better I feel whenever the E's driver can walk away.
As to his assertion that he was 'cut off' by a big rig...I'll take that one with a grain of salt...(as I'm sure the police are thinking too)
It's my experience that most drivers don't bother to pay attention to trucks. When you see a truck with it's signal on wanting to change lanes, don't try to 'beat him', just so you won't be stuck behind the truck! The truck driver is watching the space, and when he see's he's clear, he will change lanes. He may not see you accelerating to take the space.
Were you cut off? Technically, no, you shouldn't have been speeding up to take the space (obviously on the inside lane too). You should have let the truck change lanes, then passed him when the way is clear.
But it's so much easier to say 'The big bad truck cut me off!' More correctly, you were not watching the road and traffic ahead of you, and failed to see what was going on.
Either way, the result is the same...car argues with truck, car loses. Always.
/rant