I took this photo many months ago, but still think it's worth mentioning. It's located at the intersection of Forest Avenue and Bedford Street, next to the USM library.
Are there similar installations at other Portland intersections? I do not know. I do think it's a novel idea and it was the first time I have seen it in Portland. A 'no turn on red' sign would make this safer for pedestrians, but I think it does plenty and it is a million times better than the old intersection layout that had right-turning (from Bedford to Forest) traffic yielding/never stopping. Also, being an extension of USM, I'm sure the flashing sign works well during peak pedestrian times such as between classes.
I also like how this intersection had a median separating both sides of Forest Avenue, which provides a much needed (albeit very small) shelter from vehicles while crossing 4 lanes.