My layout generally models the steam era from 1930 to 1955. I bought some street traffic signals to erect at a few road intersections in town, but then it occurred to me, where were they back then?
Traffic signals were not hanging from a wire stretched across an intersection in the steam era. I remember the traffic lights on the sidewalk at the corner, so I did some research.
These pictures are of New York City in the period of 1930 to 1960. Note that the signals have only red & green lights, no yellow. Also notice that the green light is on the bottom.