I have seen different color traffic lights....in Washington DC, they all are darkish grey, I've seen New York areas....have some green ones, in my area and in Illinois have black front face and visors with yellow backing, Columbia area in Maryland some are and were actually brown, but some had replaced with yellow ones!
Ontario used to have some green signals but I think most of them are now gone except for some smaller flasher lights. We use mostly yellow ones now but some places use black signals to blend in better.
we have Zero Green Signals in Tyler....we use Mostly Black signals with Yellow's Mixed in....Black is Nice...but i Prefer Yellow to Black...and Green to Yellow...it Blends in Nicely with Folliage like Tree's and such...Yellow Sticks out like a Big Sore Thumb.
We had green signals here. I know that one three-lens signal remains, but is disconnected. Another one has been repainted silver, and we still have those GE school lights in original green.
We have green signals here in British Columbia,the signals on the mast arms have yellow trims,but the ones mounted with brackets on the side of the poles are green signals minus trims.
Here's a shot of some now removed green signals on Hwy. 10 in Mississauga at around 3:50 in this youtube video from 1989. There's also some dayburning MV lights in the video too.
You could also see a still existing green warning flasher with a sign light on this old railway overhead here in streetview.
You could also see a still existing green warning flasher with a sign light on this old railway overhead here in streetview.