Several automakers have come under fire in recent years over reported EPA gas mileage figures that prove unattainable in the real world.

According to the Wall Street Journal, the EPA plans to require car manufacturers to road-test new cars to confirm gas-mileage ratings based on laboratory tests that they submit to the EPA.

2013 Ford Fusion Hybrid, test drive, Catskill Mountains, NY, Mar 2013

2013 Ford Fusion Hybrid, test drive, Catskill Mountains, NY, Mar 2013

The EPA is "establishing a regulatory requirement" for road testing, according to its spokesman, to minimize the potential for consumer dissatisfaction when real-world gas mileage differs significantly from the ratings on window stickers.

The move follows recent cases surrounding Ford, Hyundai and Kia, all of whom have had to restate mileage figures following customer complaints.

According to Automotive News, a discrepancy between window sticker figures and real-world mileage is among the most frequent customer complaints dealt with by the EPA.

Ford recently cut the official gas mileage figures on six models, in response to criticism that its hybrid and plug-in hybrid vehicles, along with the 2014 Ford Fiesta, struggled to hit their quoted ratings.

Those reductions followed--but were unrelated to--earlier complaints regarding the Ford C-Max Hybrid, whose gas mileage had been slashed from 47 mpg combined to 43 mpg combined last August.

The C-Max Hybrid had fallen through a loophole in EPA regulations that allows cars with the same drivetrain to carry the same figures. Ford had used those from the sleeker Fusion Hybrid, leading to greater inaccuracy between quoted figures and real-world results.

2011 Hyundai Elantra Limited

2011 Hyundai Elantra Limited

Hyundai and Kia also came under fire in 2012 when several of its models failed to hit official EPA figures in testing. The companies put this down to procedural error, but a full 13 models had their figures amended and the Korean automaker set aside $395 million to reimburse affected owners.

The EPA’s director of the Office of Transportation and Air Quality, Chris Grundler, told The Wall Street Journal that some automakers already road-test their vehicles to verify mileage ratings--but the EPA plans to make it a regulatory requirement.

As well as improving the accuracy of measured figures by including factors like air resistance and rolling friction, it would also reduce any occurrence of automakers manipulating lab results to deliver high gas-mileage claims.

The goal would be a system that more accurately reflects the real-world gas mileage owners might achieve once they hit the roads in their new cars.


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