Just for fun, on your 172mpg trip to Watkins Glen, your grams per mile of CO2 emissions was 58.7gpm tailpipe, 74.9gpm wells to wheels. It would be 17.6gpm wells to wheels if you ran 100% biodiesel with a 76.4% lifecycle reduction in CO2 compared to petroleum diesel fuel. Biodiesel also burns far cleaner from the tailpipe than Petroleum based diesel regarding other pollutants.
For reference my car doing 70mpg in the summer does 158gpm, and the average passenger car in the US emits 423gpm. At 172mpg and 74.9gpm, your CO2 emissions are just 17.7% of the average car on the road!
