As someone with more than a basic understanding of technology and how self driving works, I would think the end user would take special care driving in fog since the car relies on cameras to identify the roads and objects. This is clearly user error.
Even if they did, they’d get to the polls and their names wouldn’t be on the voter registration list so they’d either be told “You can’t vote, you’re not a citizen” if they admit they aren’t a citizen or told “Here’s a provisional ballot” if they lie and say they are a citizen; which would then be thrown out once votes were actually tabulated since it wouldn’t clear the registered voter rolls