3rd Mar 2024

Dieselgate: How carmakers were allowed to bend the law

  • Cars in Europe are polluting more under conditions that many would consider normal, like when it is colder than 17 degrees Celsius outside (Photo: José Pedro Costa)

Despite public outrage after Volkswagen Group (VW) admitted in September 2015 that it had cheated on emissions tests, little is being done to bring any suspects to trial.

National authorities across the EU have continued a hands-off approach towards the use of switch-off or defeat devices in cars that deliberately diminish the effect of technology explicitly designed to prevent environmental damage.

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  • 'No evidence that other manufacturers are using software of the type used by Volkswagen' - but they did have defeat devices (Photo: Volkswagen)

Car manufacturers have swerved punishments by arguing that their switch-off devices comply with EU regulations – an opinion hotly disputed by campaigners, but apparently accepted by national governments.

Transport ministers will debate the perceived legal uncertainty involving switch-off software on Tuesday (7 June) in Luxembourg.

The debate comes nine months after VW was forced to admit in the US that it had equipped its cars with software that changed the behaviour of the emissions control system to give lower outputs during tests.

Authorities in Europe were inspired to do their own investigations. The German, UK and French authorities set out to check the emissions of dangerous nitrogen oxide (NOx) from diesel cars.

The results of these three probes were published in April, and all three yielded similar results.

“As matters stand at present, the field investigations do not indicate any further defeat devices that are based on a test-cycle recognition,” the German transport ministry report said, referring to the method VW had adopted for cheating.

The UK's minister for Transport Robert Goodwill also seemed relieved.

“Importantly our testing has found no evidence that other manufacturers are using software of the type used by Volkswagen. This finding is a significant step forward in assuring drivers that the serious breach of trust committed by Volkswagen is not more prevalent,” Goodwill wrote in his report.

No, the others perhaps did not use the exact same software. But that was a false reassurance, research by EUobserver found.

The UK's report clearly stated that it had found “higher levels of nitrogen oxide (NOx) emissions in test track and real-world driving conditions than in the laboratory for all manufacturer’s vehicles”.

Similar results were found in Germany and France.

'It is to protect the engine'

When confronted with the test results, the car makers all gave very similar excuses in relation to the emissions control system, which reduces the release of toxic gases.

The higher emissions on the road could be explained because the emissions control system was switched off or switched to a less powerful mode under certain conditions.

These conditions, however, were staggeringly normal.

The emissions system of the V6 version of the Audi A6 worked less hard when outside temperatures were below 17C. The Fiat Ducato 3.0 when it was between 20C and 5C.

The Hyundai ix35 was emitting between 4.4 and 6.2 times as much on the road as in the lab, the German investigators found. Hyundai explained that the emissions control system's effectiveness depended on “numerous external and internal factors”. These included ambient temperature, humidity, engine speed, load, coolant temperature.

These switch-off mechanisms were all, in fact, so-called defeat devices, which are banned under EU law.

The relevant EU legislation defines a defeat device as “any element of design which senses temperature, vehicle speed, engine speed (RPM), transmission gear, manifold vacuum or any other parameter for the purpose of activating, modulating, delaying or deactivating the operation of any part of the emission control system, that reduces the effectiveness of the emission control system under conditions which may reasonably be expected to be encountered in normal vehicle operation and use”.

Recognising temperature, among other things, is exactly what car makers have been doing to limit the use of the emissions control system.

The report by the German transport ministry said “all manufacturers use defeat devices as per the definition” in the regulation.

Luckily for the manufacturers, the regulation has an exemption from the ban when “the need for the device is justified in terms of protecting the engine against damage or accident and for safe operation of the vehicle”.

The argument that the device is needed to protect the engine is used comprehensively, and is explicitly accepted by the German transport ministry. Their UK colleagues also seemed satisfied with that explanation.

“We were told by manufacturers that the emissions control strategy for NOx is less effective at lower temperatures in order to ensure durability and protect the engine from damage,” the UK report said.


But both the durability and the engine argument can and should be challenged, according to lawyer Remo Klinger. He investigated the issue for German non-profit green group Deutsche Umwelthilfe (German Environmental Aid) and published his legal opinion in March.

The argument that car makers should be allowed to temporarily switch off the emissions control system to make sure that the system itself does not break does not hold up.

Klinger wrote that the regulation already assumes the “permanent durability of the devices”.

If an emissions control system is only durable when it is turned off under certain conditions, then the car manufacturer must “adopt other technical systems, or if it is unable to do so it must refrain from building such diesel engines”.

As for installing a defeat device to protect the engine, Klinger noted that this is only allowed “if the device is necessary”. So how do you define necessary?

There are also cars on the market, for example in the United States, which have an emissions control system that does not have to be switched off. That, Klinger writes, “proves that the use of the switch-off device is not absolutely necessary in order to protect the engine from damage”.

Moreover, some of the manufacturers promised the German ministry that they would provide a software update, showing that technologically, the defeat devices were not absolutely necessary.

Finally, the legislation clearly says that the emissions control system must work under normal conditions.

Normal conditions in Europe often includes outdoor temperatures below 17 °C. According to non-profit group Transport & Environment the average temperature is 9 °C.

(Photo: Transport & Environment)

“Nobody would seriously argue that a switch-off device which reduces braking effectiveness or changes the door locking system under low outdoor temperatures is permissible,” wrote Klinger.

Yet, it seems that several of Europe's national authorities are accepting this argument when it comes to the emissions device.

Rules are too vague

Germany explicitly said in its April report that the EU legislation was too vague, arguing that it did not consider the rules to provide the legal backing to go against the car companies.

“The fact that the constituent element of 'normal use' is linguistically very vague allows room for interpretation,” the German transport ministry wrote.

“A consequence of the vagueness of this European regulation could be that the use of defeat devices could ultimately always be justified by quoting the protection of the engine if the manufacturer explains in a comprehensible manner that without such a device there is the risk of damage to the engine, however small it may be."

“The regulations governing defeat devices which have been applicable so far cause legal uncertainties among manufacturers and are not a sufficient basis to help type approval authorities to distinguish between lawful and unlawful defeat devices and to take legal action against the latter.”

The significance of these statements cannot be underestimated.

It means that the German transport ministry, the authority ultimately responsible for making sure only cars complying with EU legislation are allowed on the market in the EU's largest member state says it cannot police and enforce the ban on defeat devices.

Concerns weren't raised before

It took the German transport ministry nine years after the regulation came into force to publicly make this observation.

It would be like finding out nine years after banning car thefts that the police had no way of proving if someone had stolen or just borrowed a car because the law was too vague.

According to an EU commission official who requested not to be named the commission is open to a discussion about whether the rules are precise enough.

“But let me also say that the letter and spirit of the Regulation is clear in that defeat devices are banned and can only be used in exceptional circumstances defined in the legislation,” the official noted.

The source added that the commission had “never received in the past any request from member states or from car manufacturers raising questions about the interpretation of these rules”.

But wait, it gets worse.

In October 2015, two witnesses gave testimony in the UK House of Commons' transport committee.

Ian Yarnold of the UK Department for Transport said: “We need to reflect for a moment on what a defeat device could be.

“It is not as though you can see this thing on the side of the engine, and it has a label or something. It is actually very difficult to find a defeat device.”

Paul Higgs, chief executive of the UK's car type approval authority, the Vehicle Certification Agency, agreed. “It is extremely difficult to find,” he said.

“You have tens of thousands of lines of code. We would need a forensic analysis of the actual source code itself. Even then you would struggle to find where the actual defeat device was hidden.”

In the car-theft analogy, they would be the police officers who cannot detect the crime.

Tips from Prague

But Michal Vojtisek, an engineering academic at the Czech Technical University in Prague, told this website in an interview that finding a defeat device does not require scouring “tens of thousands of lines of code”.

No, a defeat device can be proven by way of deduction.

“If you have a very strong suspicion, the state or European authority should ask the manufacturer to prove it that it is not a defeat device. They should ask the manufacturer to provide the justification,” said Vojtisek.

“Why are you disabling exhaust gas recirculation after 20 minutes of driving? Why do you have triple or quadruple nitrogen oxide emissions? What is the technical reason? That should be scrutinised. If there is no technical reason, then it must be a defeat device.”

The Czech expert has been involved in emissions measurements for 20 years and was one of the developers of the first portable emissions monitoring system (PEMS), which allowed researchers to find the large gap that exists between emissions on the road and in the laboratory.

What few people realise is that the Environmental Protection Agency in the US did not find the defeat device in the car's software, but rather confronted VW with the inexplicable discrepancy between on-road and lab emissions. But still, the EPA played it well, said Vojtisek.

“When EPA went public they knew enough that they could prove in court that there is a defeat device, that is my opinion,” he says.

“They were well-prepared and also – this is also my opinion – maybe Volkswagen admitted it because the evidence was very sound and conclusive.”

If it looks, smells, and feels like a defeat device, it probably is a defeat device.

It all comes down to interpretation.

Vojtisek recalled a previous case of defeat-device use almost two decades ago in the United States, with diesel trucks.

“When the first dieselgate happened, there was no definition of a defeat device,” Vojtisek said.

“The court ruled that if emission standards are put in legislation, then it was not intended for real driving emissions to be totally independent of emissions in a laboratory. Otherwise the legislation is useless."

“The purpose of those limits is to improve the air quality by lowering emissions. That is my interpretation of the legislation, and that is probably how it would be interpreted in the United States. I see no reason why we should say anything differently in Europe.”

Years of inaction

However, the responsible authorities have apparently done very little in the past nine years to check for defeat devices.

The German transport ministry announced in the report that the Kraftfahrt-Bundesamt (Federal Motor Transport Authority) would begin doing random tests itself – until now it had left this in the hands of commercial laboratories, whose role in the car approval process has been viewed by critics with suspicion, out of fear they embody conflicts of interest.

Czech expert Vojtisek noted that allowing cheating is also a competitive disadvantage to the honest car maker.

“If one cheats, and it is allowed, or they get away with it, there is no punishment, and they save some money, they can make the car cheaper, then it is an incentive for the others to do the same,” he said.

Happy ending is still possible

The 7 June debate between EU ministers may reverse the apathy.

Transport ministers will discuss the exceptions in the regulation.

"We think there is probably a need for more clarity on the extent of these exceptions," said a source close to the EU presidency, which chairs Tuesday's meeting. He noted that the commission may be asked to provide "guidance to member states on how to interpret the existing legislation".

A presidency discussion paper noted that "it is important that NOx emission reduction systems are only switched off in exceptional circumstances" and that the burden of proof should be on car companies.

"There should be an obligation for car manufacturers to prove why NOx emission reduction technologies need to be switched off in their car models, while under similar circumstances these technologies are still operational with other car manufacturers," it said.

On Thursday (2 June), Belgium's Walloon region published the results of its research into the differences between on-road and lab emissions. Virtually all tested diesel cars emitted on average three to four times as much as the limits allowed.

"We are being deceived by the automotive industry," said Walloon minister for transport and environment Carlo Di Antonio.

That anger may translate into ministers calling on each other's responsibility, although that remains to be seen.

"I cannot tell you that there will be any soul-searching. There might be, but I am not in the position to do any predictions on that, I'm sorry,” the presidency source said.

How the car industry won the EU's trust

Car companies are allowed to do carry out some testing of their own products thanks to some little-noticed legislation inspired by an industry-backed report.

One year on: Dieselgate keeps getting bigger

One year ago, it emerged that VW had cheated on emission tests in what came to be called the Dieselgate affair. EUobserver looked at how it happened and what the EU did to stop it.

Emissions cheats face tiny fines in some EU states

Fines for car firms that cheat tests in the EU range from €7 million to €1,000. EU commission itself unsure to what extent states complied with rules on "dissuasive" penalties.

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