I grew up a twice that far from New Orleans and called it a Po’boy. But that came from my parents, who lived in a New Orleans suburb for a few years. Most people called it a sub sandwich where I grew up and eventually I changed over to that.It's very accurate, but I could have predicted that: the linchpin question was the sandwich description. As a general rule, no one outside of a 150 mile circle around New Orleans calls it a po-boy, but that's one of the few truly Louisianian expressions I've never been able to shake (mostly because they are just so darned GOOD there. It's the bread.) If I hadn't had that very unique answer on my list, I think it would have had a lot less accuracy.
The trick for me was "do I answer it with what I'd prefer to say, or with what I would need to say to make myself understood where I live?" I kind of split the difference, because I've been here 30 years now.
The city listed for me was within 60 miles of where I grew up.