Scientists from the European Commission have found evidence that carmakers manipulated the results of a carbon dioxide emissions test.

According to documents obtained by Transport & Environment (T&E), evidence was found that car manufacturers cheated the results of the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) in order to inflate their results in the carbon dioxide emissions test, either by declaring higher results than they had registered or by reconfiguring test vehicles.

Europe switched from the NEDC carbon dioxide emissions test to the WLTP test in recent years to give a more accurate estimate of emissions during real world driving scenarios. Because of the methodology in the latter test, results were expected to be higher, meaning that less scrutiny was applied to carmakers potentially over-reporting or manipulating their results.

Why would car manufacturers report higher CO 2 emissions?

The potential cheating that the Commission detected is of concern because the WLTP is the foundation for calculating 2025 and 2030 decarbonisation targets for the European car industry. The target for 2025 is a 15% compared to emissions in 2021, and if carmakers manipulate their results ahead of the 2021 milestone, they could make their targets in terms of emissions less ambitious.

This means that companies could sell more greenhouse gas-emitting vehicles and fewer electric vehicles without struggling to meet their targets, while also decreasing the contribution to combating climate change that vehicle manufacturers need to make.

How did Transport & Environment react to the discovery?

William Todts, executive director of T&E, called on the Commission to investigate the practice of cheating emissions tests more thoroughly, including the possibility that car manufacturers are working together to subvert the EU’s climate ambitions for the transport sector.

He said: “After Dieselgate carmakers promised to change and that new tests were the solution. Now it’s clear they’re using these new tests to undermine the already weak CO2 standards. They want to meet these with minimal effort so they can keep selling diesels and delay the shift to electric cars. The only way this trick can work is if all carmakers work together… Fixing the baseline problem isn’t enough; there need to be sanctions to end the industry’s endemic cheating and collusion.”