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 |  Jan 07 2012, 10:00 AM

The statistics for the new Dodge Dart seemed a little to good to be true, because that is exactly what they are. One of the stipulations in the Fiat takeover was that Chrysler needed to develop a car with at least 40 mpg before the Italian automaker could lock down more shares in the American company.

The numbers posted for the Dart are not completely made up, however, they are the EPA’s CAFE numbers. What this means is that the EPA tests the car and gives it a Corporate Average Fuel Economy, (CAFE) rating, not a real world rating.

NHTSA breaks down the classifications on there website, “Three different sets of fuel economy values- NHTSA’s CAFE values, EPA’s unadjusted dynamometer values, and EPA’s adjusted on-road values exist. NHTSA’s CAFE values are used to determine manufacturers’ compliance with the applicable average fuel economy standards and to develop its annual report, the Automotive Fuel Economy Program Annual Update. The EPA’s unadjusted dynamometer values are calculated from the emissions generated during the testing using a carbon balance equation. EPA knows the amount of carbon in the fuel, so by measuring the carbon compounds expelled in the exhaust they can calculate the fuel economy. EPA’s adjusted on-road values are those values listed in the Fuel Economy Guide and on new vehicle labels, adjusted to account for the in-use shortfall of EPA dynamometer test values.”

What that all means is that the first numbers to come out are the CAFE numbers, which are influenced by many factors including the amount of vehicles produced. Then the dyno numbers are released, which are closer to real world stats. And finally the cars are tested on the road to figure out what the real fuel economy will be.

Dodge released its CAFE fuel economy numbers for the Dart, which are a little more optimistic than the real fuel economy rating will be. While a 40 mpg highway rating for the new Dart is possible, look for an average in the mid-30s when the car debuts Monday at the Detroit Auto Show.

To find out more about the EPA and fuel economy numbers, click here.