You're not going to get a list of every circumstance. That's not the way life works. It's certainly not the way government works. And, increasingly, it's also not the way the law works.
Well let's take another look at your earlier comment "Except that the 'safe distance' isn't always the same amount of space in all circumstances. It might be considered necessary to leave a greater safe distance because of the fact that you're following a truck up a hill."
You chose to disagree with my comment, and I'm just trying to get you to substantiate what you chose to say but now suddenly 'that's not how life works'. Isn't that a bit ridiculous?