I also expect people to go "Yank-Tank" on the remaining used cars so long as there's fuel to be bought or made. We're all getting poorer thanks to our jobs going overseas to nations with slave-labor economies, sometimes literally. Most of us can't afford to pay civilized nation's labor prices and keep our vehicles running so we end up doing that ourselves. I suspect most of us are going to end up learning the maintenance requirements for our chosen hardware. And until such time as ultralight cars are both cheap and legal, modifying existing ones to use less gasoline, through hyper-mileing and "adding lightness" as Richard Hammond would say, is the way forward. That means cutting off fenders and replacing with fiberglass or plastic, replacing heavy glass windows with thin plastic ones, and adding structural support beams (aka scaffolding) so the car is still rigid enough to work. It's the future. With lighter cars, you can run narrower tires and somewhat higher pressure. The Cardboard Car on Wired was an amazing bit of kit. Picture that running on a 200cc lawnmower or Honda scooter engine. Yanmar makes a 6 HP diesel you could run on cooking oil you've turned into biodiesel. The cardboard and plywood car is pretty much what a Tuktuk is, only shorter. Tuktuks are still made in India and Japan, though they're famous for rolling over. Mini/Micro-trucks are safer and just as gutless, though largely illegal on roads due to how slow and unsafe they are. Again, if it's a choice between slow and starving to death, most people choose the inconvenience.
At some point we're going to have to grow up and accept that life isn't safe. We're all going to die sometime. No mom thinks jogging in the Sierra's with her Ipod on is a life risking activity, but then again, they don't often think about the cougar waiting to pounce either. Considering it is in the best interests of the