Hi again Clay,
In the UK we may not travel so many miles as you do in the US, but we drive faster, the 70 mph national speed limit is only adhered to when a police car is visible and we spend a lot of time sitting in traffic jams with engines running.
Last September I spent 2 weeks touring New England in a V6, covering 2300 miles and think how cheap gas was, however not as cheap as several years ago when I remember paying 99 cents for a gallon!
Over here a own a 2 litre Mercedes turdo diesel with CVT auto transmission. I tend to drive more sensibly and economically than I used to, even at 70 mph I can get over 50 mpg, my record is 58 mpg. Very similar figures to the supposedly green Toyota Prius.
John