I was practicing take off's and landings this summer at KDET which is right in Detroit, in a Cessna 172. I could see all kinds of insulators on poles flying around. Although in the picture you really can't see any, but they're out there. The road in the picture that goes from the bottom to down town is Gratiot. You can kind of see some of the old light poles along it. Probably a couple of them are the wood light poles. Yes, a wood street light! Detroit has a lot of them.