March 26, 2006

Your mileage may vary -- and how!

It's time to revise the federal gas mileage rating methodology.

Have you noticed how the official gas mileage ratings on cars are absurdly optimistic? For example, my 1998 Honda Accord was supposed to get 20 miles per gallon in the city and 28 mpg on the highway, but I average about 17 mpg, maybe 18 mpg overall for mixed city and highway driving, so my annual gas consumption is about one-third higher than the federal government told me it would be.

My guess is that the government's mpg testing methodology has gotten progressively less realistic. I'd bet that the test comes from the mid-1970s and assumes 55 mph on the highway and relatively unimpeded city driving. I live in the same neighborhood where I started driving three decades ago and I certainly stop and start far more now on both the freeways and the surface streets due to increased congestion. But when I do find an uncrowded freeway, it's hard to drive less than 70mph without getting run over by everybody averaging 75-80mph. Not only is the 55mph speed limit legal history in most places, but cars are better built today and can now go 80mph safely and quietly, so people do it more.

This outdated test means that vehicle buyers don't realize how expensive unaerodynamic and heavy SUVs will turn out to be. The huge 2006 Ford Expedition doesn't sound so bad at 14mpg city, 19 mpg highway, but I bet you actually get more like 11 or 12 mpg overall. Considering as well the non-monetary costs of oil consumption for the environment and foreign policy, is it too much to ask that the government tell us the straight story on mpg ratings?

My published articles are archived at -- Steve Sailer

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