We where discussing this today at work, body's just don't up by them selves, the PTO has to be engaged (why on a freeway?) and making lots of noise as well as lever in the up position with the rear trailer selected (believed to be second trailer in a B double set), again, why on a freeway?
Another line of thought was that both body's where left partially up over night, that is common, so rain doesn't puddle up in the body, and the driver drove off forgetting they where up, as he was driving the oil bleeds out of the ram on the front body and feeds the ram in the second body making it higher, either way I can't help think this was massive driver error, and as for second truck, that driver has sustained injuries and that's unfortunate, however, is he also BLIND?

how could he not see and work out things aren't right?? massive fail there too.
Engineers will now have to inspect the bridge for structural damage.
This oversight by the driver is gunna be expensive