The Garden State Parkway runs North-South, and as the highway cuts through the entire state, it is a useful orientation. So if someone in New Jersey would ask you, "where do you live?" and you would reply "Florham Park," chances are that the person asking doesn't know the place. There is an easy way out though: just ask "what exit?", meaning "what exit from the Garden State Parkway do you live at?"
That's what many people do. It comes in quite handy that exits are not enumerated consecutively but by distance. Exit 27 is about 12 miles away from exit 39.
In case you need to know, we live at exit 145.