I'm with you Rich. Using the cars as cover is a very important tactical concern.
Increasing the distance between yourself and the possible assailants is also prudent. Distance favors the trained marksman.
Also, scan the area for possible allies waiting to pounce from a hidden position or outflank you.
Personally, I like to walk to the car with my hand resting on a Smith & Wesson Model 640 Centennial in my pocket that I carry as a backup. If surprised by an assailant, I can always shoot through the pocket or at least have my hand on my gun. If time permits, then the heavier caliber primary can be brought into play.
Above all, if you have the time and distance, get in the car, start it, and get moving. A moving 3500 pound car has infinitely more stopping power than anything you can conceal on your person.