O que significa street smart?

I was listening to a podcast called Conan O'Brien needs a friend earlier tonight and as a way to introduce the episode, the host (or maybe I could call him the podcaster) came up with a few descriptions and adjectives to describe the new guest. Among the many things he mentioned, a certain term caught my ear: street smart. What does that mean?

The thing is, before I get into the term let me point out that the guest for that episode is a very famous rich celebrity from show business who is pretty much expected to have everything handed to on a silver platter. But she doesn't. Why?

She doesn't forget where she comes from: a very poor family of immigrants coming to the United States for a better living. The fact she suddenly found herself in the middle of many dangers in urban life forced her to find a way to develop knowledge and experience to handle things well. So that's why she was called street smart. 

If you handle urban life just as easily and know when to ask questions, who to trust, which way to take, be polite and defend yourself, you are also street smart. That's a kind of knowledge you don't learn from the books or in a classroom. Only out in the streets.