Gas Mileage: Overrated

I never thought I'd say this, but America has become too obsessed with gas mileage. Prius owners use their real-time mileage readout to try and get the absolute maximum number of miles out of every tank; politicians talk dreamily of cars getting 100 miles to the gallon; and even seasoned Detroit auto journalists have started going mileage crazy. Here's David Kiley, reviewing the Smart Fortwo:

The Fortwo has the best fuel economy of any gasoline-powered car that's not a hybrid, but its EPA ratings of 33 miles per gallon in the city and 41 mpg on the highway are far worse than I would expect for such a small package...
Call me a dreamer, but for a car as small and expensive as the Fortwo, I'm looking for 45 mpg/city and 52 mpg/highway, at least.

The Smart car, remember, is an urban runabout. It's not designed to commute hundreds of miles a week on highways, it's designed to get you around town efficiently. So let's do some basic sums here.

Assume that the Fortwo is driven 100 miles a week, entirely in stop-and-go city traffic. At 33 miles per gallon, that's 3 gallons of gas. As 45mpg, it's 2.2 gallons of gas. The difference, of 0.8 gallons of gas, will cost you about $3.

Now, all things being equal, would it be nice to save $3 a week on gas? Yes -- but of course all things are not equal. In order to get the Fortwo up to 45mpg in the city, Daimler would have to charge more for the car -- much more than I'd be saving in gasoline costs. Alternatively, they might have to make the engine less powerful. But given the number of highways which snake through US cities, there will always be some highway driving in the Fortwo, and Americans are going to want to keep up easily and not feel underpowered in those situations. Even in its present incarnation Kiley describes the Fortwo's power as merely "OK".

All of which is to present yet another example of why gas mileage should be inverted. Instead of expressing a preference for 45mpg over 33mpg, Kiley would instead be preferring 2.2 gallons per 100 miles over 3 gallons per 100 miles. To Americans currently using 5 or 6 or 7 gallons per 100 miles, that last 0.8 gallons might not seem like as big of a deal. Only once we've got the average car up into the 30s does it make sense to start worrying much about going even further, into the 40s or 50s or even 100s.