The EPA hopes to avoid future fuel-economy scandals, by giving the public more information about its audits of the data submitted by carmakers.
After claims of overly-optimistic mileage from Ford, Hyundai, and Kia, the agency plans to release the results of about 20 recent fuel-economy audits to the public, Automotive News reports (subscription may be required).
The audits were meant to double-check the results of the "coast-down" test, which was the source of the controversy over exaggerated Hyundai and Kia fuel economy numbers last year.
The test involves accelerating a vehicle to 80 mph and then letting it coast to a stop. All makers conduct this test, but according to an industry source, there are only two test tracks in the U.S. available to the EPA that are long enough for the test.
The coastdown test provides data on the aerodynamics of a vehicle, the rolling resistance of its tires, and drivetrain friction; its results are used to calibrate a dynamometer for the other fuel economy tests.
The EPA began regularly auditing test results three years ago, as fuel economy became a more important factor for buyers.
2013 Ford C-Max Hybrid, Catskill Mountains, NY, Oct 2012
However, this is the first time the results of the EPA's audits will be made public--giving buyers a clearer view of how the testing works, and giving rival carmakers a chance to scrutinize each others' work.
The tests will include around 20 new cars and light-trucks, and will take place at Chrysler's Chelsea Proving Ground in Michigan and at two test tracks in Arizona.
The EPA says it will translate the raw data into "plain English" for public consumption.
The decision to release the results comes after a string of fuel-economy scandals.
Both brands reported higher gas-mileage numbers than their cars actually achieved in testing, and were forced to reimburse customers.
Ford had to lower gas-mileage numbers for the 2013 C-Max Hybrid after owners were consistently unable to achieve its 47-mpg rating in real-world use. Its turbocharged EcoBoost engines have faced similar criticism.