The EPA's coast down test requires vehicles to roll from 80 miles per hour to a stop. Automakers' engineers collect data on the model's drag, rolling resistance, and drivetrain friction. The information then goes into a dynamometer for the mandated fuel economy test. The EPA set stricter guidelines for the test in 2015 starting with 2017 model year vehicles, which might help avoid similar scandals here in the future.
The EPA, 'will be directing the company to conduct additional coast down testing for vehicles sold in the US.'
Japan has also used a coast down test since 1991, but Mitsubishi recently admitted that it hadn't been following the evaluation's mandated protocols there. Instead, the automaker came up with its own "high-speed coasting test." By selecting favorable values from the results, the company was able to artificially inflate the fuel economy of at least four Japanese minicars.
In addition to inquiries from CARB and the EPA, the National Highway Traffic Safety Administration has also requested similar details from Mitsubishi. However, there is no evidence yet of any fuel economy irregularities for vehicles in the US. These agencies are just checking things out in reaction to the massive scandal in Japan.
Mitsubishi execs are trying to weather the storm, though. Chief Operating Officer Tetsuro Aikawa and CEO Osamu Masuko have denied rumors about resigning over the scandal, according to Automotive News Europe citing a Reuters report. "It's my responsibility and my mission to put the company on track to recovery," Aikawa said. Their decision came despite the automaker's stock losing half of its value since the fiasco started, and vehicle orders in Japan have dropped significantly, too.