Popular Mechanics has joined USA Today in offering gallons per hundred miles (GPHM) in its car reviews. Popular Mechanics included g/100m as one of "25 Bold Ideas" in their July issue.
The July 16 post ends, "The difference in the mpg ratings doesn't reflect the actual difference in fuel consumption the way that gallons/100 miles does, pure and simple. And that's why PM is starting to report fuel economy this way on its recent test drives. Pointedly, the EPA should promote this system too. Sure, it's trivial to calculate the difference, but with the current emphasis that car manufacturers, government agencies and consumers are placing on fuel economy, we need to change our way of thinking from high mileage to low consumption. "
If you are interested in learning more about gas savings from a trade in, please go to this May 29 post.