I've already seen a few videos of 18-wheelers traveling too fast for conditions (snow, fog, ice, heavy rain, etc.) and having stuff like that happen. I'm not sure what is going through their head when they drive like that in poor visibility.
When I'm in my coach or pulling my snowmobile trailer with the truck I try to always remind myself that there is no stopping on a dime and to leave plenty of room to avoid the unexpected.
What drives me nuts is when I leave plenty of room for myself and some moron decides to squeeze in between me and the vehicle in front of them.