The pile ups happen because someone slowed down. As much as you want to, you don’t slow down in fog. I hate driving in dense fog. It is the worst. One time I just took a chance that what I saw was an exit. Luckily it was. Until then I just followed the tall lights of a truck in front of me at 50 mph.
Doesn’t it depend on the extent of the fog? The incident I described as having experienced (in the EXACT same vicinity of SE Texas, thirty years ago), you could not SEE the road in front of the car’s hood. The hood ornament was almost unseeable. Seriously. The only way to even stay on the road was going around ten miles per hour, with my head half-outside the car window, just to spot the stripes on the road. And the highway was a virtual levee, with swampy marshlands on both sides. Nowhere to turn off. Hair-raising experience. Worst I’ve ever encountered, bar none. Unreal.
Wow.. Good luck, pal.
Advise that at least 98 drivers in this wreck followed.
I had two occasions like that: one was in Spain, where I had to look down through my opened driver's door to look down to follow the center line. While creeping along, it didn't occur to me that someone else—coming from the opposite direction—could have the same idea!
The other was recently in Florida, needing to cross a 4-lane highway. I rolled both windows down and listened for traffic before crossing. :-/