The Bay Area is an extremely fuel-consumption conscious culture for two reasons. First, prices are upwards of $2.50 per gallon, which isn’t the highest in the nation, but still pretty bad. Furthermore, people here are just very environmentally aware. Therefore, the area is flooded with Priuses, Civic Hybrids, Mini Coopers, and other efficient vehicles. There’s also a significant number of cars modified to run on biodiesel. The one below advertises that fact. Apparently it’s not very difficult, or expensive, to have your engine converted. Then you can run your car on vegetable oil waste, which you can usually get for free from restaurants and the disposal of which is a problem in its own right. I’m not getting the sled (II) modified any time soon, but maybe if I still had sled I, I’d consider it.