The General Court of the European Union overturned the emissions compliance levels under the new Real Driving Emissions (RDE) regulation in a verdict announced on 13 December. On the surface of it, this may look like a victory for cities wanting to be tougher on emissions of nitrogen oxides (NOx) from passenger cars and vans. In reality, it has the potential to further complicate the Euro 6 regulatory stage and thereby create the unintended consequence of making it even less usable for urban vehicle policy.
While the European Commission did not seek to increase the headline 80 mg/km emissions limit for diesel vehicles, which must still be adhered to in the laboratory test, they granted “Conformity Factors” that in effect did increase the limits for the harder, on-road part of the test. As a result, all diesels vehicles only had to meet 168 mg/km by September 2019, falling to 114 mg/km by January 2021. This was in practice a large increase in the permissible emissions limit.
The Court verdict suggests that vehicles already certified under Real Driving Emissions (that starts with the stage known as “Euro 6d-temp”) will remain compliant, as will vehicles certified for up to 14 further months in the future, depending on whether the Commission appeals and the speed with which replacement legislation is brought forward.
But what is this likely to mean in practice?
Let us assume that there is no appeal and no new legislation, meaning vehicles must meet 80 mg/km on the RDE test. Taking a sample of 30 RDE-certified diesel cars tested by Emissions Analytics on its independent EQUA Index test, we conclude that up to 90% of the vehicles would still be compliant. Although the test does not include cold start in its ratings, overall it remains a good proxy for RDE compliance. Furthermore, the average NOx on a combined cycle of these still-compliant vehicles is just 50 mg/km, well below the certification standard. Of the remaining 10%, they all come from the same OEM, Honda, which would in this scenario need to make changes.
This suggests the impact would be low. However, RDE does not become mandatory for all vehicles sold until September 2019. Therefore, it is likely that this conclusion is flattered due to a self-selecting sample of the best performing cars. If we look at the wider population of pre-RDE Euro 6 diesel cars, we may have a proxy for the challenge to each manufacturer of no Conformity Factors.
The table below shows the proportion of pre-RDE Euro 6 diesels from a range of manufacturer groups that meet various emissions levels, on our real-world scale. For example, 33% of all BMW/Mini Euro 6 diesel vehicles tested by Emissions Analytics achieve a rating of ‘A’.