I live at the slum's edge, basically. And I go through some really "interesting" areas on my daily run at 6am or so. In my experience, the dealers and hookers and gangsters are almost always off the streets at that hour. I've run into the occasional drunk/ high person, but very rarely. The few people out at that hour are respectable hard-working folk just going to work. So it's really no big deal. Now in the evening it's a different story; up until sunset I'll go almost anywhere on bike (but not on foot). After sunset I'm a bit pickier.

The good news: at least where I live, there are a lot of people who use bikes as their only vehicle in these very poor neighborhoods. The bad news: most of them have no idea about the rules of the road or how to ride safely. Like stopping for lights and stop signs and riding with traffic....