The transition from NEDC (New European Driving Cycle) to WLTP (Worldwide Harmonized Light Vehicles Test Procedure) was a gradual process aimed at providing more realistic consumption and emission values. The NEDC, used since the 1980s, was progressively seen as outdated because the test conditions no longer reflected real driving conditions. The WLTP, introduced in September 2017, aims to offer more realistic conditions.
There are several reasons why vehicle documents after 2017 may still contain NEDC values:
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Transition period: The introduction of WLTP came with a transition phase in which vehicles already certified according to NEDC could continue to be sold with these values. This phase allowed manufacturers to sell off inventory that had been tested under the old standards.
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Stock vehicles: Vehicles produced or registered before the official switch to WLTP retain their original NEDC values in the documents, even if they were sold after 2017.
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Conversion from WLTP to NEDC: For a transition period, values measured according to WLTP were converted to NEDC equivalents to ensure comparability with older vehicles and meet tax and regulatory requirements. This practice resulted in vehicles produced after 2017 still displaying NEDC values in their documents.
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Regulatory differences: In some countries, the regulatory requirements for the switch to WLTP were introduced at different times, which could have allowed vehicles in certain regions to be sold with NEDC values for longer.
Overall, the presence of NEDC values in vehicle documents after 2017 reflects the transition period and adaptation to the WLTP standards, which are more accurate and stringent.