So, funny story: it ISN'T ever signed as N 56th St north of the interstate. (I didn't believe it either at first.) There is no intersection signage anywhere north of the interstate; all crossroads are signed in the median and thus do not show N 56th St. This is made even stranger because S 12th St signs DO exist frequently along the old Cornhusker Hwy (US 77 south of Lincoln) and Rokeby Rd signs along the Werner Expwy (N 2). Matter of fact, one of the direction signs for N 56th St as one exits the interstate specifically points only south of the interstate. And OSM policy is that it must be signed. I went ahead and changed it to unsigned_ref, as I do think a few maps do call it that (not the first time GIS was wrong!).