Looks like a construction truck on the side of this Russian highway decided he'd go ahead and merge into the middle of the road without looking to see that another truck was barreling down on him. Big mistake.
The more I watch this crash, the gnarlier it looks. Amazingly the driver of the truck that gets hit looks oblivious to his impending doom right up until impact.
Crash at about 1:45.
Hat tip to Carscoops!