Mercedes-Benz, Honda, Mazda and Mitsubishi have joined the growing list of manufacturers whose diesel cars are known to emit significantly more pollution on the road than in regulatory tests, according to data obtained by the Guardian. But don’t expect an immediate change: Automakers are asking for more lenient emissions standards if real-world testing becomes the norm. They sell thousands of vehicles every year.
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Certain vehicles from Honda, for example, were tested on the road by Emissions Analytics and found to have had over 20 times the NOx limit than in previous tests.
In testing, Emissions Analytics analyzed about 50 Euro 6 diesels and 150 Euros 5 diesels and found only five had real-world NOx levels that matched the regulatory test.
However, US regulators are looking into whether companies-including Chrysler, General Motors, Land Rover, and Mercedes-Benz-used them, though all have denied their use.
“Since real-world driving conditions do not generally reflect those in the laboratory, the consumption figures may differ from the standardized figures”, a Mercedes-Benz spokesperson told the Guardian.
What’s worse is that in this case, they did so legally: The testing procedure in Europe was structured in such a way that NOx emissions from the cars in the lab were found to be acceptable, while on the road, they were pumping out much more. Mazda flunked by about three times while Mitsubishi was over the limit by about 3.4 times.
A Honda spokesperson told the Guardian that the company tests cars in accordance with European legislation, and a Mazda spokesperson said Mazda tries to make sure all its vehicles comply with emissions regulations.
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“The issue is a systemic one”, says emissions expert Nick Molden on the inability of diesel models to test out at proper emissions levels. Only last week, there were reports in the media that diesel cars from Nissan, Hyundai, Renault, Volvo, Citroen, Fiat, and Jeep were all producing significantly more NOx. It now seems like the emission problem is more deep-rooted than previously believed.
