I posted this in another thread (can't find it) but seem absolutely relevant to rehash for this one.
When my mother was in her early to mid 50's she was attacked twice in parking lots. Once three BG's came up to her car and tried to get her purse, etc as she was coming back from the market (this is at night). She would always bring our dog with her, so she opened the car door and our dog got out and made sure two of the men ended up in the hospital. The third ran and, yes they were armed.
The second time she was actually in her car, parked with the windows open. She was looking down going through her purse for something when a guy reached in and tried grabbing her. Again, our dog was in the car and came over the front seat and made sure that man saw the inside of an ER.
I know its not always practical, but when possible, get a large dog and take him/her with you when ever possible. They are an AMAZING deterrent and with very little training will protect you and your family. Incidents like these are NOT limited to women and have happened to many men I know...hence why I take my dogs with me when I can because I am concerned about the same thing and it works wonders around people who get my spidy senses going.
The dog mentioned above was a very sweet lab who loved my mother dearly...and as proved, would do anything for her.