Group Says Many Diesel Makers Are Manipulating Emission Tests

Volkswagen AG isn't the only diesel maker who has used software and technology tricks to meet emission standards, the European Federation for Transport and Environment asserts. It describes VW's admitted cheating on U.S. rules as "just the tip of the iceberg."

T&E bases its claim on data from the International Council on Clean Transportation. ICCT's emission tests led to VW's admission on Tuesday that it equipped 11 million diesels worldwide with software to cheat government emission certification tests.

T&E says significant gaps between lab-test emissions and real-world emissions appear in diesel-powered vehicles from several other European carmakers. It believes those gaps hint the companies have deliberately rigged their vehicles only to perform well in official lab tests.

The environmental group says the result has been fuel economy ratings from the official New European Driving Cycle that are 40% better than what drivers can expect on the road for both diesel and gasoline-fueled vehicles. T&E also estimates only 10% of diesels currently on the road operate below their nitrogen oxide emissions limits.

T&E notes that tests by ICCT showed that a diesel-powered European-spec Audi A8 large sedan emitted 22 times as much nitrogen oxide as allowed. Emissions for diesel versions of the BMW X3 crossover and Opal Zafira Tourer MPV were about 10 times over the limit.

The group claims road tests show nitrogen oxide emissions are about 50% above laboratory test levels for the BMW 5 Series sedan, Peugeot 308 five-door hatch and almost all Mercedes-Benz models.