You speak as if there were such a thing as an average woman.
Touche. I mean, "Yes, Ma'am!"
As far as self-defense is concerned, I think pepper gas, taser, running shoes - and the initial training + refreshers in using them is probably the most effective way to go.
From what I've observed, most people have an aversion to hitting another person. That, plus the human tendency for initial denial of an unpleasant and out of context event such as a car wreck or a physical attack puts the "victim" so far behind the time/power curve that you need to escalate.
And, of course, as has been mentioned before, situational awareness is key - and run when you can!