Low emission zones: Driving ban for all Euro 6 diesels?

What initially started as a technical problem under the bonnets of some vehicles has now developed into a far-reaching scandal for the entire diesel segment. The European Court of Justice (ECJ) has already spoken out forcefully on this issue several times. In July 2022, the Court declared defeat devices such as thermal windows illegal because they lead to an increase in emissions above the permitted and expected threshold. In fact, their use is illegal if they serve to reduce exhaust gas purification under normal operating conditions - and consequently to disguise the real pollutant emissions of diesel vehicles. And last November, exhaust gas manipulation again became a topic of the ECJ when it ruled that environmental associations may take legal action against the registration of cars with thermal windows.  

However, studies and emission tests repeatedly show how widespread this practice was and still is. They make clear what impact it actually has on air quality and the environment - as well as on the structure and effectiveness of the regulations that govern climate-protecting traffic measures. Much greater than expected - as a recent study by the international environmental research association ICCT points out - are the consequences of exhaust manipulation through defeat devices. It is no longer only certain vehicles of some car companies like Volkswagen and Mercedes-Benz that are involved in the scandal. Most diesel vehicles would actually manipulate their actual emissions, according to ICCT researchers, as variants of defeat devices have been applied to almost all diesels. Nearly all well-known manufacturers had probably installed such devices in order to whitewash the exhaust emission values - the study says.  

On the basis of various studies and with the help of a large test database, the Environmental Research Association was able to come to the shocking conclusion that over several years diesel cars led to unplanned and excessively high exhaust emissions in Europe. In the evaluation of exhaust gas measurements, strongly increased nitrogen oxide values were found in most cars with diesel engines of the Euro 5 and Euro 6 classes. Specifically, a good 85 percent of Euro 5 and 77 percent of Euro 6 diesels were found to have "suspiciously high emissions" in the exhaust test. In 40 percent of the cases, there were even "extreme" values for harmful nitrogen oxides (NOx), which almost certainly indicate the use of a defeat device.  

But even less elevated values indicated, according to the study by the research association, that an engine calibration strategy could have been used in numerous diesel cars. This was also classified as a prohibited defeat device by the European Court of Justice. The ICCT therefore considers it "very likely" that up to a total of 150 car models with diesel engines would have a built-in defeat device. This would correspond to approximately 8.6 million vehicles in Germany alone.  

More than 8 million cars would then have received a type approval from the Federal Motor Transport Authority (KBA) by mistake. The office is now itself affected by Dieselgate and legal action has already been taken against it - namely because of the KBA's involvement in the re-registration of various fraudulent diesels after a now inadmissible software update. More than 100 proceedings against the KBA's type approvals are already pending, he said. "The Federal Motor Transport Authority and the responsible Federal Ministry of Transport have for many years put the profits of the diesel companies above the well-being of the people" - comments Jürgen Resch, Federal Director of Deutsche Umwelthilfe (DUH). The ECJ ruling thus obliges "the Federal Motor Transport Authority to order a hard retrofit or alternatively the decommissioning of the vehicles", Resch further explains. Immediately, however, before the removal of the inadmissible defeat devices, the KBA is to bring all diesel cars of the Euro 5 and 6 emission standards into compliance with the applicable regulations.  

All in all, the ICCT study and the Court's ruling could have far-reaching consequences for car manufacturers and authorities. The conditions have also changed under which it is possible for owners of diesel cars with defeat technology to claim damages. In the eyes of the ECJ, carmakers should in future also be liable if they have simply acted negligently without any intention to defraud. However, the implications for the laws and measures that already regulate traffic and thus the emissions of the most polluting vehicles can be estimated to be even greater.  

The results of the analysis by the Environmental Research Network cast not inconsiderable doubt on how many vehicles are actually affected - and how long the car manufacturers have been more or less culpably violating numerous emissions regulations. For example, by allowing vehicles with illegal software to drive in environmental zones, they ultimately led to an increase in pollution and thus harmed air quality. For although the environmental badge is valid even if the vehicle is one of those affected, it is clear that such emissions violations pose a threat to the environment - as well as to the goals that traffic measures such as driving bans and environmental zones fundamentally pursue in terms of climate protection.  

Until thermal windows and all other forms of illegal emissions regulation are taken out of circulation once and for all, political action is required. In order to limit and compensate for the damage that has been and may still be caused by the exhaust gas manipulations. Since the authorities now assume that most diesel cars have an illegal defeat device, the government should take additional measures in the interest of more effective regulation of diesel traffic.   

The developments in the emissions scandal could thus lead to the extension of already existing environmental zones or to more vehicles being directly affected by the restrictions. This is primarily because the tightening of environmental zone regulations and the expansion of active diesel driving bans have proven several times to be one of the most effective means of reducing emissions - according to environmental experts. Diesel driving bans of this kind are already in force in cities such as Stuttgart, Munich, Hamburg and Darmstadt. In view of the current developments in Dieselgate, extending these to the whole of Germany and tightening them at the same time would be the next logical step for the traffic light government in this sense. The same also applies to the European Union, as the problem of emissions manipulation in the diesel segment affects more than a single national market.  

Overall, the decision of the EU Court of Justice is an important milestone in the fight against the diesel scandal and climate change in general. It shows that even large car companies can be held liable for their violations of the applicable emission standards - and that they cannot shirk their responsibility towards consumers and the planet. Moreover, the ruling and corresponding studies from environmental research institutes repeatedly highlight the need for stricter emission standards and better regulation of the automotive industry. For only in this way could the environment and the health of the population be shielded from polluting exhaust gases and irreversible climate damage.  

After all, pollution and climate change are seen as an unavoidable challenge for this and future generations. A global problem that can ultimately only be remedied through joint action and joint thinking. Whether Germany will ultimately decide to introduce a preventive driving ban for all diesel vehicles in the Euro6 class for this purpose remains to be weighed up by the authorities.