A short while ago, the European Parliament had the opportunity to have a closer look at the Volkswagen emission scandal. Apart from requesting Volkswagen to provide full disclosure, demands have also been made for the speedy introduction of new emission tests within Europe, which better present driving conditions (so-called Real Driving Emission – RDE tests).

Exhaust emission standards and health and environmental issues associated with them, have not only been a concern within the European Union since the VW scandal became known to the public. In many cases, the standard and real consumption as well as the standard and real emissions of vehicles do not correspond; however, these deviations seem to be the norm rather than the exception.

In May 2015, the Member States of the European Union agreed to the proposal by the European Commission in principle, to introduce vehicle emission tests under real driving conditions. The idea is to also measure nitric oxide emissions whilst driving. This regulation shall come into force in September 2017.

In 1997, fuel consumption in accordance with the Euromix formula was replaced by the values of the New European Driving Cycle (NEDC). Applying this method, fuel consumption as well as vehicle emission is determined only based on the emissions discharged on a chassis dynamometer (rolling road). However, on this artificial “road” only the wheels move – but not the vehicle itself. The driving resistance has to be created artificially in this laboratory situation. Even though the driving style has been pinpointed during this testing process (for example the exact acceleration and times of gear change), the weight of the vehicle or the energy consumption of the air conditioning system are not taken into account. The framework conditions too are not particularly strictly defined, so that any “legal” optimisation of the test results by the car manufacturer is admissible. Increasing the tyre pressure, using special low-friction oils or not charging the battery are just some of such variants. NEDC, as a relative consumption and emission benchmark has been developed on the basis of strongly idealised and fuel efficient driving. However, consumers do regard this consumption data as genuine, as car manufacturers openly advertise their products based on these values.

The attempt, to measure consumption and emission values (also) whilst driving outside test conditions, must be welcomed from environmental aspects, from the point of view of consumers and with regard to general health. However, it has to be ensured that car manufacturers are subjected to tight controls and that no optimised vehicles will be used; hence that there is a standardized and verifiable testing process, which does not give manufacturers any room for optimisation.

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