VDA’s model calculation reveals individual effects in detail – greatest effect from software updates
“The measures approved jointly by politicians and the automotive industry at the diesel summit on August 2 – coupled with vehicle replacement – can bring about a tangible reduction in NOx emissions from road traffic in Germany within the foreseeable future. By the beginning of 2019, total NOx emissions from road traffic could be down by 12 to 14 percent compared with the level at the beginning of 2017,” stressed Matthias Wissmann, President of the German Association of the Automotive Industry (VDA). He added that this would require all stakeholders to play an active part – including policymakers and motorists.
The VDA has undertaken a model calculation to assess three separate effects in detail. It reveals that the software updates for Euro 5 and Euro 6 diesel cars represent a major factor: at 7 percentage points, they will make the largest contribution to reducing NOx. Second, the trade-in bonuses are expected to contribute up to 2 percentage points. Third, with 4.3 percentage points, there is the “natural fleet replacement” by new registrations of Euro 6 vehicles. The sum of these effects is an overall potential for bringing down total NOx from German road traffic of 12 to 14 percent within 24 months. “That would be a very large improvement in the air quality in Germany. And most importantly, it will take effect after a relatively short time,” Wissmann underscored.
In its analysis the VDA assumes that the software update will lead to an average NOx reduction of 27.5 percent per vehicle. In the case of the trade-in bonuses for drivers of older diesel cars (Euro 1 to Euro 4), the VDA has assumed that around one in ten drivers could take up this option, although it has to be borne in mind that some of them would have replaced their cars anyway. Another assumption in the VDA’s calculation is that within this group, approx. 60 out of 100 drivers of older diesels will switch to new Euro 6 diesels and approx. 40 will switch to new Euro 6 gasoline vehicles or alternative powertrains.
The VDA based its emissions calculations on the NOx emission factors according to the “Handbook Emission Factors for Road Transport” (HBEFA, version 3.3, last revised in April 2017, published by the Federal Environment Agency [UBA]). The HBEFA determines the average real emissions behavior of the vehicles on the roads, and not the NOx values measured on the test bench.
“This painstaking analysis shows that at the diesel summit we are definitely dealing with effective instruments that are also much more intelligent than banning vehicles. Driving bans would affect many motorists who bought new cars only a few years ago. Neither the politicians nor the industry wants that,” Wissmann said.
The air quality in Germany has been improving all the time. For example, according to the UBA nitrogen oxide emissions from road traffic in Germany already fell by around 70 percent in the period from 1990 to 2015.
The great improvement in air quality resulting from the continued market penetration by the most modern Euro 6 vehicles – independent of the decisions at the diesel summit – is shown by another study by AVISO and the Technical University of Graz, whose results were published recently (“Modelling the effect on air quality of Euro 6 emission factor scenarios“, Journal of Earth Science and Geotechnical Engineering, vol. 6, no. 4, 2016, p. 227-244, see also:
The study was supported by the Ministry for the Environment, the UBA, the Federal Highway Research Institute (BASt), the Institute for Energy and Environmental Research (ifeu) and the VDA.
The results of the study show that “natural fleet replacement” alone – not including effects of the measures passed at the diesel summit – will result in a continuous improvement in air quality. This fleet renewal will lead to more and more measuring stations remaining below the permissible NO2 limit value. In 2020, only 39 of the 144 measuring stations near road traffic will not comply with the NO2 limit value. Five years later, 12 stations will exceed the limit. This shows that the technical measures for achieving Euro 6 and RDE are effective.
Wissmann emphasized, “The trade-in bonuses and the software updates will accelerate this natural fleet replacement by several years.”
These measures – supplemented with local emissions-reducing instruments such as digital measures that improve the flow of traffic and reduce the volume – will resolve the issue of air quality in towns and cities within the foreseeable future.