But when I bought my last car, I looked squarely at the L/100km measurement. I did the math. And I realized that for what I'd save in the ticket price between buying a 2007 Chev. Aveo (which I did end up buying) over buying something like a Smart car or a hybrid, I could pay for the total gas I'd use over the entire lifetime of the car. The difference between 6L/100km and 3.8L/100km just isn't *that* significant, and certainly isn't significant enough to justify spending another $15,000 on a car that probably won't see 100,000km in its entire 5 year lifetime before I trade it in for a new one. The price of gas would have to be 7x what it currently is for that to have become an economical proposition.
The choice for an Hybrid or a fuel efficient car should not only take in to account the cost of the fuel, but also the cost to the environment. If you add the cost of a "carbon fee" for the extra fuel you burn, for the energy required to bring that fuel to you, the damage to the environment to extract that fuel, you get quite a good deal...
Everything that can be invented has been invented. -- Charles Duell, Director of U.S. Patent Office, 1899