Separate walking?

Today, I was walking between offices in Brooklyn.  As I was walking, and looking around at the stores and other buildings, and of course searching for random license plates, because who doesn't look for random license plates on every walk they take?!  So I was walking, minding my own business, when I suddenly noticed that as I was walking on the north side of the street, there were only men on my side of the street.  On the south side of the street, were lots of women and no men.  I've heard of separate seating, including on a bus, where I also get into trouble.  But can it be that Brooklyn is sooo frum that they have "separate walking"?!