Because of the shortcomings of the current car emission test, the European Union is finalising a new test, called the Worldwide Harmonised Light Vehicle Test Procedure (WLTP). With the WLTP, testing conditions will become much more realistic.


All these elements will make the WLTP test more accurate than the current lab test (NEDC).

When will WLTP be introduced?learn more

WLTP will apply for new types of cars from September 2017 and for all car registrations from September 2018. However, before the WLTP is implemented, a number of issues need to be resolved by the EU.

The key issues are:

  1. Labelling: ensuring a smooth transition in the system of labelling from the current test (NECD) to the future test (WLTP), so that the customer is not confused.
  2. Data collection: there are challenges on how to collect NEDC and WLTP data reliably from all 28 EU member states, in order to legally monitor compliance with the CO2 fleet targets.
  3. Future standards: as emissions will be measured differently in the future, governments need to ensure that CO2-based taxation will be fair in the transition period between the old and the new lab test.

To resolve and address the above challenges, the European Commission is currently working on a correlation exercise to determine how CO2 measurements using the new WLTP can be translated back to a CO2 number of equivalent stringency based on the NEDC, since the legal fleet average target will remain at 95g CO2 per kilometre given that it was agreed on the basis of the NEDC test.

In the future, a complementary test for pollutants will be conducted on the road: RDElearn more

Lab measurement of pollutants will change from the NEDC to the more representative WLTP. However, the lab tests will be complemented by the ‘Real Driving Emissions’ (RDE) test, which will ensure that vehicles deliver low pollutant emissions, not only in the laboratory but also on the road.

RDE testing of cars on real roads under realistic driving conditions will be a new addition to the existing testing requirements, making Europe the only region in the world to implement such an on-the-road test.

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Even though WLTP will be more accurate, it will not cover all the variations globally – and certainly not each individual driving style. There will therefore still be a difference between emissions measured in lab conditions and the real world, as driving behaviour, traffic and weather conditions will continue to differ from one country to another.