The European Real-Driving Emissions Regulation

Published Mon, 2015.12.28 | By

Vicente Franco, Peter Mock


In January 2016 the EU Parliament will evaluate the RDE proposal from the European Commission's Technical Committee on Motor Vehicles (TCMV). This brief notes five things that could strengthen the regulation.

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Beginning in 2017, the European Union’s emissions type-approval procedure for passenger cars will include a new Real-Driving Emissions (RDE) test conducted using on-board portable emissions measurement systems (PEMS). The RDE regulation is a key policy to address high real-world emissions of nitrogen oxides (NOx) from diesel cars, but its success will depend on the ability of regulators to adjust its stringency level to drive changes in emissions control technology.

Setting the bar too low for the RDE test will not dispel new doubts arising over "clean diesel," and it will effectively penalize manufacturers who are using the best available NOx control technologies. RDE provisions should reflect the state of the art in emissions control technology, and be progressively reviewed until real-world emissions and legal emission limits are in line, as is already the case for most regulated pollutants.

In January 2016, the European Parliament will evaluate the proposal that emerged from the October meeting of the European Commission's Technical Committee on Motor Vehicles (TCMV). Against that background, we note five actions that could strengthen the RDE regulation:

  1. Expand the focus of the RDE regulation from type-approval only to in-use testing for compliance and enforcement purposes. Vehicles for in-use tests could be obtained at random from private individuals by enforcement agencies, and tests could be conducted throughout the useful life of vehicles to monitor the durability of emission control systems.
  2. Revert the conformity factors to the initial technical consensus proposal made by the European Commission to Member States in the TCMV meeting of October 2015: a NOX conformity factor of 1.6 in 2017, and 1.2 for the final conformity factor in 2019.
  3. Accelerate the technical work to include cold-start emissions in the RDE test results evaluation method, with the intention of setting specific, legally binding limits by 2019. Controlling cold-start emissions is especially relevant for air quality in urban environments.
  4. Monitor and expand the boundary conditions (e.g., ambient temperature, altitude, dynamic driving indicators) of the RDE test procedure. Experience has shown that driving situations not covered by regulations can lead to uncontrolled yet technically legal emission behaviors, and this is especially true of NOX emissions, which grow exponentially outside of the operating conditions covered by the design of the aftertreatment systems and their control algorithms.
  5. Improve public access to information and provide incentives to foster clean technologies.

Unless technology neutrality (i.e., equal stringency of emission standards regardless of engine type) is achieved, regional and local authorities could be compelled to devise disincentive programs—including bans—for diesel cars. By trying to protect the diesel car industry in the short run, Member States may in fact be compromising its long term viability.

Though the proposed conformity factors are above the levels that current technology can reasonably achieve, the provisions for their annual revision offer a means to bring them down to more closely reflect the state of emissions control technology. In spite of its current shortcomings—which should be addressed in future amendments—the RDE regulation is a commendable effort by the European Commission, and makes the EU a pioneering region in the use of on-road tests for emissions type-approval. The ICCT therefore welcomes it as a major step forward in addressing Europe’s air quality problems.