Report suggests automakers besides VW cheated emissions, too

Assembly of a Mercedes-Benz engine
Assembly of a Mercedes-Benz engine
Image: Mercedes-Benz

Now that Volkswagen has admitted to cheating U.S. emissions testing on its four-cylinder TDI diesel engines, some reports are beginning to scrutinize and question the real-world diesel emissions of other European car brands.

Until this point, it's been believed that cars fitted with "urea treatment" systems, an emissions-cutting additive, including those from the Volkswagen Group, would not be implicated in the scandal, as the technology is believed to reliably cut tailpipe emissions in diesel cars. It was this technology critically missing from the VW models fitted with "defeat devices."

Now, however, the Transportation and Environment (T&E) organization, a European group that claims to be dedicated to promoting sustainable transportation, is questioning that belief. Citing a study by the International Council on Clean Transport (ICCT), the group that originally discovered that VW was cheating emissions tests, T&E concludes that some automakers lag behind others in real-world emissions.

Additionally, in a report published Monday, T&E compiled data from "respected testing authorities around Europe" that show several European automakers, including Audi, BMW, Mercedes-Benz, and Opel (a General Motors brand) might, too, sell cars that produce illegal levels of tailpipe emissions.

T&E stated that real-world emissions testing showed drastic differences from laboratory tests in Europe. "A diesel Audi A8 tested in Europe produced nitrogen oxide emissions 21.9 times over the legal limit on the road; a BMW X3 diesel was 9.9 times over the limit on the road," and "an Opal Zafira Tourer, 9.5 times."

In real-world testing, every Mercedes-Benz model produced 50% more CO2 than in the laboratory, T&E claims, while the BMW 5 Series diesel model emitted just shy of 50% more on the road than in the lab. "For virtually every new model that comes onto the market the gap between test and real-world performance leaps," the report asserts.

T&E has outlined ways carmakers are able to manipulate emissions tests. Brands "charge the car’s battery before a test, deduct 4% from each test result, and use incorrect laboratory settings for the inertia of the vehicle."

None of the automakers implicated in the T&E report immediately responded to a request for comment.