Trucks like that are specifically designed not to flip, believe it or not they have a pretty low center of gravity, the engine is placed low, and the cab is very light. Also it had some sort of cab suspension, did you see it compress going around the turns?
Very cool nonetheless, you know his arms had to be tired @ the end of that run. Now i've seen it all w/semi's, 1st road racing, then the Drakkar, now drifing, thats just nuts.