I just moved from a city with a heavy police presence and no red light cameras to one with them placed sporadically throughout the place and almost no police presence (massively understaffed department) and I see far, far more runners in my new city. I see a handful a day. I quit walking to work. I think it's got a lot to do with driving culture/police presence as well. People get surprised when they get red light tickets. Maybe the cameras should look more obvious.