[Ntrails]

_Personally_ the only time I care about mpg is when looking at how far I can travel on a tank of fuel. Or, when the fuel warning light comes on (you have 5L of fuel left, how far is that going to get you).

In essence I'd argue that most of the use of the any fuel efficiency metric is to simply rank cars, rather than to ever back out a genuinely useful cost/distance number. At which point furlongs per quart would be as effective as anything else...