Wow, that really surprises me. Now I'm thinking Americans must be driving in the dark in foggy situations, or are you required to stop your vehicles when sight

Wow, that really surprises me. Now I'm thinking Americans must be driving in the dark in foggy situations, or are you required to stop your vehicles when sight is limited? I mean, I realize that fog lights can give you a false sense of security, not everything is illuminated, but I found them very useful. I'm thinking extreme situations, like ten meters visibility on the Autobahn.