I asked one of my martial arts instructors about personal self defense in the parking lot. He's a great fighter, and a fulltime cop. He showed me the following items that he had on his person. The first was a flashlight. He shined it into my eyes in broad daylight outside, and it was BRIGHT. Just a quick flash, and I had a bad sunspot obscuring my vision for many seconds thereafter. I think it would badly blind someone at night. It's specifically designed to do so actually.
There are many different models of this flashlight. You can find them
here
Another very nifty item is this pepper spray. It's simply the best designed pepper spray I have ever seen. The safety is extremely easy to pop off and it blasts out from the bottom. Check it out
here at ASP's website. They also sell collapsible batons, which are srsly illegal in CA, but may be permissable for you in your state. Check your local laws before purchasing and carrying.
Stay safe guys [img]/images/graemlins/smile.gif[/img]