So it's been said that listing our cars as miles per gallon is kind of foolish, since people don't buy a specific number of gallons and then drive until they run out, they pick somewhere to go and drive until they get there. So it makes much more sense to list fuel efficency in gallons per 100 or 1000 miles. In fact in Canada and England cars are rated as litres per kilometers. Now this doesn't sound like much. Just a change of units, some simple math. But I was thinking about the simple math, and yah, it is simple, but it's also very powerful psychologically because people default to thinging about relationships being linear. I made this image to drive my point home. The bottom number is mpg. The top is gallons per 100 miles. And yes, it's approximate.
It was bugging me enough that I needed to post it. I'm not sure what to do with my revolation. But I guess it really struck me that the prius, which is ~50mpg, uses one less gallon per 100 miles than my old saturn, at ~30 mpg and my new car, at about ~25mpg, uses one more per 100 miles. And I know I did this math when thinking about my purchase, but it just hadn't struck home that my "oh, it's just 5mpg" was a whole gallon! Driving to pittsburgh, at $4/gallon, that's $24. On the other hand, that 25mpg I gave up compared to the prius only gets me $48... so...
