I've only experienced freezing fog one time in my life and it was bizarre. It was incredibly foggy outside, and nearing freezing temps. I went down through a "holler" or low spot in the road while driving and my windshield immediately froze over, almost had to pull over and clean it off but it disappeared nearly as quickly as it came on after about 20 seconds, which is an eternity when you're in a car going 35mph and can't see! Luckily I was on a back road in the middle of nowhere and no other cars around. I was more concerned about trees and deer.
