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Informed user

  • In the European Union, vehicle models undergo a certification procedure – the type-approval – before they are introduced to the market. During type-approval with respect to pollutant emissions and fuel consumption, each vehicle model is tested in the laboratory. For pollutants, according to EU regulation, the type-approval also includes on-road measurements with not-to-exceed values. The pollutant, CO2 emission, and fuel consumption values measured during these tests are reported as the official environmental performance of each vehicle model.

  • The type-approval is granted by one of the Type-approval Authorities (TAA). Each EU Member State has one. Vehicle manufacturers are free to choose which authority does the type-approval for their vehicle. Manufacturers are responsible for the type-approval testing, witnessed either by the type-approval authority, or a technical service appointed by the type-approval authority. The test protocols are fixed and established in 2007/46/EC, also known as the ‘Framework Directive on the type-approval of motor vehicles’. Emissions and fuel consumption are established by following the Worldwide Harmonised Light Vehicles Test Procedure (WLTP). For WLTP, but not for NEDC, the type-approval CO2 emission is checked via emission samples taken in the factory. Once the vehicle is allowed on the European Roads there are no further checks on the type-approval performance or fuel consumption.

  • The type-approval procedure used to be based on the New European Driving Cycle (NEDC), which was designed in the 1980s. All CO2 emission targets so far have been set based on the NEDC. Because the NEDC was considered outdated, along with an increased gap observed between real-world and official fuel consumption, the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) was adopted in September 2017. Compared to the NEDC, the WLTP better matches on-road performance. However, because the 2020 CO2 emission targets were set for NEDC before the WLTP was adopted, WLTP type-approval values can also be translated to NEDC values until 2020. Users may, therefore, see two CO2 emission values. Future CO2 targets will be set according to WLTP.

  • New European Driving Cycle (NEDC) and Worldwide Harmonised Light-Duty Vehicles Test Procedure (WTLP) are laboratory procedures that measure fuel consumption, CO2, and pollutant emissions over a driving cycle on a chassis dynamometer. The NEDC had several issues, the main ones being that it had a smooth driving profile that was not representative of the real-world driving, it didn’t foresee average ambient conditions, and the effect of new technologies could be overestimated. To counteract these shortcomings, the WLTP was designed to better reflect modern real-world driving conditions with a more dynamic driving profile and temperature range. The impact of new technologies is now also assessed under real-world operation.

  • The Real Driving Emissions (RDE) test is an on-road measurement test protocol for pollutant emissions, which is complementary to the WLTP type-approval procedure. The vehicle is driven over a route that resembles real-driving conditions, including conditions such as altitude differences, year-round temperatures and variable vehicle speed. The measured emissions during the test must lie within specific limits, which are slightly higher than the laboratory values and are called conformity factors.

  • European emission standards, usually called Euro standards, regulate air pollutant emissions from road vehicles, i.e. cars, vans, trucks, and buses. Regulated pollutants include carbon monoxide (CO), nitrogen oxides (NO and NO2), unburnt hydrocarbons (HC), and particulate matter (PM). All new vehicle models sold in the EU must comply with the emission limits set by the Euro standard that was applicable at the time of sale.

  • Euro standards were first introduced in 1992 and have become increasingly stringent over the years. Every four to five years, a new standard is introduced in the EU. The main difference between one standard and the next lies in the emission limit values. For example, Euro 5 petrol cars must comply with a limit of 1.0 grams carbon monoxide per kilometre, while the limit for a Euro 6 petrol car is 0.5 grams per kilometre.

    Click here for an overview of the emission limits for passenger cars in the EU.

  • Partly because of the ‘Dieselgate’ scandal, the Euro 6 standard has been updated several times since its introduction in September 2014. Each update has been given a letter designation (‘a’ to ‘d’). Successive updates have brought changes to the emission limit values set in 2014 and/or have introduced changes to the emissions testing requirements aimed at reducing the gap between official and real-world pollutant emissions. For example, Euro 6a and 6b differ in the method used to measure particulate matter (PM), while Euro 6c included the introduction of the Real Driving Emissions (RDE) test procedure for monitoring purposes.