Scheherazade wrote this morning about the benefits of driving straight to the top of parking garages. I wholeheartedly agree and do it all the time. Since I love to walk (as has been noted on this blog by me, my daughter, and my sister), I'd like to suggest that after you park on the roof you avoid the elevator and take the stairs down to street level and back up again.
On a related note, when you go to a shopping center or mall don't drive around hoping to find a parking space near the door of the store you want to shop at. Park in the first empty space you happen upon and walk. I promise you that you'll be inside shopping before the lot-cruisers are even out of their cars, and you'll use less gas. A walk of 100 or 200 extra yards not only isn't going to kill you but it's good for you.