One reason that US oil consumption has declined to 1999 levels is that consumers are buying more fuel efficient vehicles.
Consumer preference is a powerful force, and it has swept the Prius to a gaudy ranking. The once-ridiculed Prius is now the top selling vehicle of all types--cars, trucks, SUVs--in California and number 12 in the nation. Prius sales this year are up 12% in America and 26% in California. Not too shabby.