As it turns out, Volkswagen may not be the only carmaker that sold diesel-powered cars which exceeded allowed emissions levels.

A report from Transport & Environment drops the bomb, claiming more carmakers sell vehicles which exceed the European limit for air pollution.

During the past three years, Transport & Environment (T&E), with the support of the International Council on Clean Transportation (ICCT – the organization that alerted US authorities to its concerns over VW), has exposed several ways carmakers manipulate emissions tests in Europe for both air pollution and CO2 emissions.

Automakers are said to charge the car’s battery before a test, deduct 4 percent from each test result and use incorrect laboratory settings for the inertia of the vehicle. While the companies admit these tricks, they claim they are “legitimate flexibilities”. As a result, the gap between official fuel economy figures and those achieved by an average driver have grown to 40 percent.

This is why nitrogen oxide emissions for new diesel cars are typically five times higher on the road than the allowed limit, with just one in 10 cars meeting the required level on the road.

However, for some models, the gap is so large Transport & Environment suspects the car is able to detect when it is tested via a “defeat device” which artificially lowers emissions during the test.

These models include the diesel Audi A8 tested in Europe, which produced nitrogen oxide emissions 21.9 times over the legal limit on the road, a BMW X3 diesel that was 9.9 times over the limit, an Opel Zafira Tourer (9.5 times) and Citroen C4 Picasso (5.1 times). The results are really troubling considering that all these vehicles passed the laboratory test.

In CO2 tests, T&E says almost every Mercedes model achieves levels on the road over 50 percent higher than the laboratory tests. The BMW 5-Series and Peugeot 308 achieve just under 50 percent higher than in the lab.

Add a more worrying fact: for virtually every new model that comes onto the market, the gap between test and real-world performance leaps. With the launch of the VW Golf Mk7, the gap between test and real-world CO2 emissions jumped from 22 percent to 41 percent, while for the new Mercedes C-Class it rose from 37 percent to 53 percent. For the Renault Clio IV, the gap almost doubled from 19 percent to 34 percent. These results lead T&E and ICCT to believe that more automakers are using “defeat devices”.

“All measured data suggests that this is not a VW-specific issue,” ICCT’s Europe Managing director Peter Mock told  Auto Bild. The German magazine asked BMW whether it uses a similar device to that found in VW vehicles. “There is no function to recognize emissions testing cycles at BMW. All emissions systems remain active outside the testing cycles,” a BMW spokesman said.

In addition, the BMW representative said diesel-powered X5 SUVs passed similar ICCT tests in the past and added that the company was not aware that the BMW X3 was tested as well. “We will contact the ICCT and ask for clarification on the conducted road testing,” the spokesman added.

In the wake of the report, BMW shares fell as much as 9.3 percent in Frankfurt.

Update: BMW responded to these reports with the following statement on Friday, September 25:

“BMW Group is committed to observing the legal requirements in each country and fulfilling all local testing requirements.

In other words, our exhaust treatment systems are active whether rolling on the test bench or driving on the road.

Clear, binding specifications and processes are in place through all phases of development at the BMW Group in order to avoid wrongdoing.

Two studies carried out by the ICCT (International Council on Clean Transportation) have confirmed that the BMW X5 and 13 other BMW vehicles tested comply with the legal requirements concerning NOx emissions. No discrepancies were found in the X5 between laboratory-test and field-test NOx emissions.

The German magazine Auto Bild has published a clarification of their article released yesterday (September 24) concerning the emissions of a BMW X3 stating: “No evidence of emission manipulation by BMW…. The values mentioned in the document were only generated in a single, one hour-long road test. Auto BILD has no access to the details of this test trail, which might explain the discrepancies to the test cycle NEDC.”  (NEDC stands for New European Driving Cycle)

BMW Group is willing to discuss our testing procedures with the relevant authorities and to make our vehicles available for testing at any time.”

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