I'm faster and more agile on a bike than I am walking, particularly when it comes to walking from one subway stop to another. I feel safer on a bike than I do in a car, because I know how to get off a bike in an accident--in a car I'm trapped in a steel can. All in all, I prefer the bicycle over any other option.
In any case, when it comes to the kind of "personal safety" you're talking about, I am much more concerned about acquaintance ****. The people you know are more dangerous than the people you don't.