For most of the 20th Century, between about 1915 and 1965, Manhattan and the Bronx were dominated by classic “humpback” street signs in navy blue (coincidentally NY Yankee colors) with serifed lettering in white. These signs were supplanted by yellow vinyl signs with black lettering beginning in 1964 until today’s familiar green and white scheme was adopted (though today, Downtown Alliance signs in black and reflective white can be found south of City Hall, and midtown has illuminated blue and white street signs).
However, signs like you see above also had a brief reign on busy midtown avenues in the 1950s and 1960s. They were yellow-colored metal with black lettering in Highway Gothic, with the street name on top and the cross street on a panel on the bottom. Like their fellow navy and white signs, these signs were largely supplanted by vinyl signs in the 60s — though their yellow and black color scheme was retained for twenty years.