LA Auto Show: VW Up! Lite

Chuck and Saponetta: Please remember that the fuel used over an arbitrary distance is inversely proportional to mpg. This makes comparisons very unintuitive. People think linearly and mpg is nonlinear. To compare two cars, you have to take the inverse of each one's mpg rating and then subtract. That difference tells you how much you can save with one versus the other. Consider driving a thousand miles, which is somewhat less than than the national average for a month. A 15 mpg truck will burn 66.7 gallons. A truck that gets 20 mpg will use 50.0 gallons for a savings of 16.7 gallons. Over the same distance, a 33 mpg Civic will use 30.3 gallons and the 70 mpg VW will use 14.3 gallons. Compared to the Civic, the VW saves 16.0 gallons. To put it another way, a 33% improvement in truck mpg saves slightly more fuel than does the 112% improvement from the Civic to the VW. This isn't magic or sleight of hand. It's a direct consequence of the fact that mpg is a shit stupid way to measure fuel consumption. It misleads in two directions. At the low end, it understates substantial reductions in consumption. At the high end, it exaggerates marginal differences between highly economical vehicles. I don't doubt that some people are making buying decisions over a couple of mpg. They are the same ones who threw away thousands of dollars when they dumped nearly new trucks and SUVs in an attempt to save a few hundred dollars on gas. They do this because they don't (or can't) properly analyze their options. Two years ago, I was shopping for an automotive toy to enjoy through retirement. Fuel consumption was enough of a consideration that I invested several hours in building a spreadsheet that compared a broad range of candidates from a Civic to a Pontiac GTO. My analysis showed that the difference between the high and low ends was less than many people spend on cable TV or cell phones. At that point, I deleted the spreadsheet and stopped worrying. I agree that the Prius was a major accomplishment and that this VW is an engineering tour de force. However, it will do more good to replace Ford Explorers with Ford Escapes (I mean conventional Escapes, not the hybrid).

70 mpg? The Euro press release says 2.44 L/100km, which is 96.4 mpg. For the combined figure, not for highway. Math fail?