Eco-nomics: Zen and the Art of Buying a Fuel Efficient Car

In my previous quick post about pondering the decision to trade in my car for a Prius I was trying to make the simple point that MPG figures can be misleading in terms of how much going up in fuel efficiency can reduce overall gas consumption. I mentioned that a 5 MPG bump when you start at 15 MPG is better than a 20 MPG bump when you start at 30 MPG. But as I was writing it I could not help but start to think about the general equilibrium aspects of the question (I am an economist after all - once you have swallowed the red pill there is no going back). What I wrote about was really the partial equilibrium - the cost to me all else remaining the same.

The interesting comments I received make me even more curious to know the answers to questions like: What are the effects on the used car market and on overall energy consumption if high mileage cars start accumulating? What are the effects on the markets for inputs (commenter Stacy mentions Lithium mining)? What about the energy inputs into the manufacture of a new car (as Becky mentions), should trading in a relatively new car give me pause? I mentioned the Prius, but until the new one's better mileage ratings, I had assumed that a new 'clean' diesel would be the better option given the preponderance of highway driving I do (as Spencer and Oliver mention), is this a better option? What about the disposal of all those batteries (again, as Stacy mentions)? And, finally, how much should I expect from the promises of newer and better technologies coming soon? The Volt sounds pretty good, for example, but Spencer is a skeptic.

I have a feeling that many others have explored these issues and that there is a lot of information out there of varying quality. So I would like to enlist your help in answering these questions - can you direct me to sources of quality reliable information and research about these issues? I promise to write about what I discover.