Thank you sloth passer!
 

Coming up canyon in right lane after dark and a bit foggy, car starts
passing in the passing lane and then just 'hangs' there. After about a
minute I slowed to force him to get out of there. That is when we hit
the real dense fog. I had it easy, just follow his tail lights about
20 yards back, ease off when I would see his brake lights flare which
was fairly often due to denser patches of fog. When I got near my
drive (I thought I was a lot closer than I was), I dropped over to the
park lane and felt my way along counting field entrances until I
spotted my drive. I hate driving in fog after dark especially in that
old F150.

Harry K