Dieselgate: an industry-wide scandal

Since Volkswagen’s cheating was exposed in Dieselgate, more and more evidence has emerged highlighting how other companies engage in questionable practices. 


In October 2015, T&E’s German member, Deutsche Umwelthilfe (Environmental Action Germany, or DUH), revealed that Opel Zafira’s emissions were 2-4 times higher than legal NOx values when tested in four-wheel drive, while they were below the legal limit of 80 mg/km when the car was tested in two-wheel mode, as is required by the previous EU lab test. A month later DUH tested a Renault Espace that produced 25 times the EU NOx limit when run with a warm engine. However, it met the limit when tested with a cold engine after “specific pre-conditioning” – as was legally permissible under the EU test. All this suspicious data has been given to the German TAA responsible for certifying some of these vehicles, but there has been only very limited follow-up.

Dieselgate prompted T&E's member DUH to conduct testing of its own

Dieselgate cheating techniques

In early 2016 many EU countries scrutinised their emission testing programmes to verify whether other vehicles have been fitted with similar illegal software. The results of the German, French and UK investigations showed huge discrepancies between lab and real-world emissions and widespread use of defeat devices for all models tested. Yet no penalties have been levied or consumers compensated. Not only VW is involved; Renault, Opel, Ford, Daimler, Fiat and others are also implicated. T&E has summarised the main cheating techniques employed by carmakers in a briefing. In 2019 the International Council on Clean Transportation published strategies to catch so-called ‘defeat devices’ that reduce the effectiveness of emissions aftertreatment systems under real-world use.

When summoned to give evidence, carmakers usually refer to using the derogations that allow switching off emission abatement technology if it endangers the safe performance of the vehicle engine. Often this derogation is used in temperatures below 17°C, which is encountered almost 80% of the time in cities like London, Berlin and Paris. This excuse is often accepted by the national authorities, who prefer to protect home industry instead of applying the law rigorously.

Enforcement: Europe vs US

In Europe – in stark contrast with the US where the authorities are forcing Volkswagen to comply with the law and compensate the misled consumers – most politicians are behaving as if the Volkswagen scandal and Dieselgate never happened. In June 2016 a historic settlement with Volkswagen was reached in the US: the carmaker agreed to an almost $15 billion partial settlement designed to do three things: compensate consumers for advertising fraud; promote electric vehicles; and clean up excess air pollution from the nearly half a million deliberately defective diesel cars sold on the US market for seven years. In Europe manufacturers are let off the hook and get away with just voluntary recalls despite breaching the EU limits by a large margin.

Just as carmakers cannot switch off braking systems to preserve the life of braking pads, they shouldn’t be allowed to switch off after-treatment systems that control pollution in most road conditions in Europe. This is not a victimless crime. According to the European Environment Agency, more than 390,000 people die prematurely due to air pollution every year in Europe, many choked by diesel fumes.

The new test and type approval system that is being introduced stepwise will tackle some of these problems. But without political will to tackle the consequences of the Dieselgate scandal, most of the existing polluting cars will remain on Europe’s roads for years.