Bimmer and VW's Audi division are apparently the worst offenders at underreporting fleetwide emissions, says Reuters, citing a report by the non-profit International Council on Clean Transportation (ICCT).
The emissions numbers that BMW reports are about 30 percent below real-world results, while Audi's figures are about 28 percent less than what its cars are actually spewing, according to the ICCT report. Overall, automakers are underreporting emissions by about 25 percent, compared to about a 10-percent fudge factor a decade ago. Hybrid leader Toyota underestimates its cars' emissions by 15 percent.
German automakers' approach to tightening fuel-economy standards has been topical because of the companies' various public-relations approaches. Volkswagen and leaders of the environmental group Greenpeace in April agreed to bury the hatchet after VW, long accused of misrepresenting fuel-economy gains by its diesel cars, pledged to cut fleetwide emissions to meet Europe's standards for 2020.
BMW, on the other hand, has been squawking about the challenge of meeting such standards, saying earlier this month that it was "impossible" to do so without government financial assistance towards advanced-powertrain technology.