Professors from Duke University are trying to explain to Americans why we should stop using “miles per gallon,” and instead use “gallons per 100 miles” (or something similar). I’m convinced. Try their short, but effective, interactive quiz. The New York Times is reporting on it too.
Here’s the gist:
Let’s say you own a Lamborghini that gets 5 m.p.g. and a Hummer that gets 10 m.p.g. You’d like to replace one of your cars so that you’re spending less money on gas. Your two options are: (A) trade in your Lamborghini (5 m.p.g.) for a Ferrari that gets 10 m.p.g.; (B) to trade in your Hummer (10 m.p.g.) for a hybrid one-seater that gets an amazing 100 m.p.g..
The “obvious choice” seems to be (B), but some simple division will show us that we’re stupid.
Let’s assume that you drive each car 100 miles per week:
Option (A): Instead of using 20 gallons (100/5 = 20) a week in your Lamborghini, you’d only be using 10 gallons (100/10 = 10) in your Ferrari, thus you would save 10 gallons a week.
Option (B): Instead of using 10 gallons a week in your Hummer, you’d only be using 1 gallon in your fancy new solo-man hybrid, thus saving 9 gallons a week.
Conclusion: You will save more gas/money by replacing your Lamborghini with a Ferrari rather than replacing your Hummer with a single-seater super hybrid.
Now let’s tell the story with “gallons per 100 miles.”
Option (A): Replace your Lamborghini that uses 20 g.p.100 miles with a Ferrari that uses 10 g.p.100 miles.
Option (B): Replace your Hummer that uses 10 g.p.100 miles with a hybrid that uses 1 g.p.100 miles.
Isn’t this phrasing much better?