This is breaking local news on Facebook right now, and it looks like One Of Us got name-dropped in the comments.
“What exit” is a common phrase is NJ. Here you hear it fairly often.
Yeah, i used to live in NJ. I assumed you picked that name because of its ubiquity.
It’s a New Jersey thing? I hear it in California all the time.
Eta: I guess for you guys it’s some kind of inside joke?
Eta 2: wait, the usage in the screenshot is identical to how it’s used in CA
…Eta 3: because the OP is in SC, not NJ.
So it’s an inside joke in NJ and a common turn of phrase elsewhere?
…
How else would you ask, well, what exit to get off at?
I think I’ve also seen my name in an email, once or twice…
A subtle difference is that in California we tend to use the street names rather than the numbers when referring to exits. We didn’t even number them until about 20 years ago.
And New Jerseyans use the term more broadly. “Oh, you live in New Jersey? What exit?” It names a region of the state, not just a part of the highway.
But… was the 18wheeler on a treadmill?
Yeah. That usage didn’t /doesn’t fit any state I’ve lived in.
My CA time was before most exits were numbered. Although the mileposts were everywhere and most folks were aware of them. But even absent milepost awareness we wouldn’t use “I live near the Beastly Boulevard exit off the 405” as a regional descriptor.
Is that basically because NJ is so small that it’s like saying “I live off the 101”? 
No, but if you say “I found a cool restaurant in Burbank” I very well might ask “What exit?”
We’re very small and very densely populated. We have more people, cars, roads and highways per square mile than any other state.
So “what exit?” will often be answered by 105 off the Parkway or Exit 11 Turnpike as examples. The first meaning central Monmouth County and the second The Woodbridge area. The GSP (Garden State Parkway) is incremented by a lot of exits, and runs from the top of the state NY Border exit 172 down to exit 0 which is Cape May. The exits represent miles so it is actually very useful.
The Turnpike exits are less useful.
Rt 78, 80, 195, 287 & the Atlantic City Expressway are other highways that help define locations.
My years in California was also before Exit Numbers.
The Turnpike is notorious for going through some of the worst areas of the state, though it is much better looking (and smelling) than when I was a kid.
The Parkway is a whole other world, especially from Exit 120 south to Cape May. Lush and green. Also spends a long time going through the near wilderness known as the Pine Barrens.
I know that exits have numbers, but I’ve never met anyone (except my GPS) who says the exit number instead of the exit street name.
I have, as have a few other people I know. People that are used to taking a numbered exit all that time that goes to a certain street or area sometimes say “take the (insert name here) exit” not realizing that what the sign actually says is just the exit number.
Good example: Here in Portland there is a section of I-84 called “The Banfield” by locals, and I have very frequently heard people say “Take the Banfield exit”…but there are no signs on any exits, or signs on the Interstate itself, that say “Banfield”.
One difference is that California exits are based on the mileage since the freeway started or entered the state, rounded to the nearest integer and given A/B if two are the same. New Jersey is generally the same, but some roads are exceptions and sequential, most notably the Turnpike.
I have used “1920’s style Death Ray” at work to see if anyone takes the bait… So far, nobody’s called me out on it.
Tripler
I would reckon this place’d be full of Dopers.
“Which exit?”
There’s a stretch of 390 around Rochester NY which has three or four exits onto Rt 15. If you don’t want to drive through half of downtown, you need to know the exit number.