Expert group warns European authorities about excess emissions of diesel cars, including post-Dieselgate vehicles

The CARES research group has sent two open letters to European authorities to warn about excess emissions of diesel car families, including those of models sold under Real Driving Emissions (RDE) tests introduced after the Dieselgate scandal.

The open letters include the findings of remote sensing campaigns carried out in Krakow, Milan, Prague, and Brno in 2021 and 2022. Remote sensing is a contactless technology that measures the emissions of in-use vehicles and is recognized by the EU (Regulation 2017/1151) as one of the “appropriate methods” to collect information regarding possible issues of emission non-compliance with vehicle families.

In an open letter sent to all European Union type approval authorities, researchers offered new data on the excess emissions of some diesel car families (Euro 6d-TEMP and Euro 6d). Engines from Hyundai Motor Company, Ford, and PSA (Stellantis) show several times higher emissions than the best families in class. Their nitrogen oxide (NOX) emissions under urban driving conditions are also elevated compared to the respective RDE limit.

The second open letter was sent to all European market surveillance authorities, including national bodies from the EU and the UK. Based on the same remote sensing campaigns, researchers found that diesel cars certified to Euro 5 and early Euro 6 (pre-RDE) are still producing excess NOx emissions — up to over ten times the emission standard limit.

The International Council on Clean Transportation (ICCT) is a member of the CARES consortium. CARES brings together experts in non-intrusive vehicle emission measurements from 20 partner organizations in Europe and China to investigate the use of different remote sensing techniques for monitoring real-world vehicle emissions performance and compliance with exhaust pollutant standards.

Read the Open letter to all European Union Type Approval Authorities: Some Euro 6d-TEMP and Euro 6d vehicle families showing high on-road NOx emissions

Read the Open Letter to all European Market Surveillance Authorities: Diesel Euro 5 and early Euro 6 cars still showing high on-road NOx emissions

Read the CARES project’s final report 

The CARES project received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 814966.

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