Car and Driver: The Truth About EPA City / Highway MPG Estimates

Washington DC September 1, 2009; The AIADA newsletter reported that according to Car and Driver, the U.S. Environmental Protection Agency (EPA) has certified the fuel-economy projections of some 450 million new vehicles sold in this country.

The published MPG projections appear almost like a pledge from the federal government, and motorists have put a lot of faith in these numbers.

While the public mistakenly presumes that this federal agency is hard at work conducting complicated tests on every new model of truck, van, car, and SUV, in reality, just 18 of the EPA's 17,000 employees work in the automobile-testing department in Ann Arbor, Mich., examining 200 to 250 vehicles a year, or roughly 15 percent of new models.

As to that other 85 percent, the EPA takes automakers at their word—without any testing—accepting submitted results as accurate.

Car and Driver visited the EPA's lab for a look at just how these numbers are derived. What the reporters found is that determining MPG is enormously complicated. There are endless reams of documents that explain, in detail, every procedure and circumstance, and each comes with its own set of rules.

Even the procedure for rounding off the results of the fuel-economy tests to produce what is published on a new-car label is highly complex.

Click Here to read Car and Driver's full report on how the EPA estimates vehicle mileage.