No. The efficiency of the vehicles will not change as a result of the changeover to the new WLTP measurement procedure. However, the values determined under WLTP will reduce the difference between the previous NEDC consumption values and the values from road tests. Therefore, WLTP will make it possible, before buying a vehicle, for the customer to look at the individual vehicle figures in order to better estimate the average consumption and CO2 emissions of the vehicle – with optional extras also being taken into consideration. This will also allow a better comparison of vehicles.
2. Will WLTP lead to higher consumption and CO2 figures?
Yes. Vehicles with combustion engines can be expected on paper to have higher consumption and CO2 values. The stated range of electric vehicles will be reduced. There will be no change when it comes to the actual consumption experienced by customers, as the vehicles will not change as a result of the switch to the new measurement procedure.
3. By how much will the consumption and CO2 figures increase?
As part of the changeover from NEDC to WLTP, VDA (German Association of the Automotive Industry) anticipates an average increase of 20 percent in consumption/CO2 values compared with the previous NEDC values.
READ MORE: Mercedes-Benz dumping NEDC for WLTP in fuel consumption tests
4. Will the WLTP values now finally reflect the actual consumption?
The WLTP significantly reduces the difference between the figures in brochures and the average consumption values experienced by customers. Yet the WLTP values, too, are determined in the lab under defined test conditions, so that they are reproducible and comparable between individual vehicles and manufacturers. Conversely, real consumption or the consumption figures from road tests are affected by specific factors: driving style, route, weather conditions, actual laden state of the vehicle, condition of the vehicle and, of course, the volume of traffic. Therefore, these values are neither reproducible nor comparable. A road test delivers a snapshot and is in no way representative – nor is it representative of the requirements of every customer.
5. So does the same lack of reproducibility apply also to the RDE emissions tests?
The RDE road tests verify that the prescribed limits for nitrogen oxides (NOx) and particulate number (PN) are not exceeded under on-road driving conditions after the legal conformity factors are taken into consideration. An RDE test covers a wide spectrum of legally defined permissible ambient conditions. In practice, this means that, under very many driving conditions, the emissions values will be lower than the certified values. However, an RDE test does not reproducibly deliver a consumption figure that is representative for all customers at the same time.
6. Are WLTP & RDE a reaction to the VW emissions scandal? Has it taken public pressure to bring about the tighter test procedures?
No. Development of the WLTP began at UN level back in 2007, and the Joint Research Centre (JRC) of the European Commission launched the development of the RDE tests in 2011. The development of these realistic measurement procedures required a long lead time, as extensive preliminary measurement programmes were conducted. Added to this is the development of the WLTP-NEDC correlation method[1], which also took a great deal of time and effort. The correlation method is necessary in order, up until 2020, to make NEDC values available for all vehicles alongside the WLTP values. These NEDC values are required because European fleet target legislation will not change over to WLTP until the 2021 calendar year.
7. Who carries out the WLTP and RDE tests? Independent institutes? Or the manufacturers themselves or companies working for them?
The WLTP tests are carried out in accordance with the legal requirements by independent Technical Services, such as TÜV or Dekra. The Technical Service is responsible to the authority for making sure that the legal requirements are met at all times.
8. Will WLTP increase the motor vehicle tax in Germany from 1 September 2018?
Yes, because the German legislative authorities have not changed the taxation rules despite the new measurement procedure. As a result of the changed requirements, although the consumption of the vehicles is not higher in reality, it will be higher on paper. Consequently, the higher CO2 values will be included in the tax calculation without a conversion formula. This means that especially the owners of newly registered, but technically unmodified small cars can expect a sharp rise in tax. However, the impacts of the changeover to WLTP are scheduled to be reviewed after September 2018.
9. What is the position in other countries with regard to motor vehicle tax? Will they, too, see an increase?
In most other European countries with tax based on CO2 emissions, the requirements for taxation under WLTP have not yet been finalised. EU member states have until 1 January 2021 to change over their taxation regimes, because only from that date will it no longer be necessary to continue with NEDC values. Other countries, such as the Netherlands or Austria, have announced that the changeover will have no effect on the budget, i.e. the impact of the changeover to WLTP on the values of individual vehicles will first be assessed before the legal requirements are brought into line.
10. When will Mercedes-Benz start to give the WLTP-based CO2 and consumption figures in configurators and press materials?
Probably from Sept 1, 2018. As that is the date on which Germany will switch the motor vehicle tax for newly registered vehicles to WLTP, WLTP values will probably have to be given in customer information documents and systems by that date. However, there are not yet any corresponding regulations for amending the relevant German ordinance (energy consumption labelling ordinance, Pkw-EnVKV). In any case, NEDC values must continue to be given until at least the end of August 2018, even though a vehicle has already been certified according to WLTP.
11. How will fleet emissions limits be calculated in future?
The WLTP cycle will mean an increase in nominal CO2 emissions. Since, however, the EU has already set fleet targets up to and including 2020 according to NEDC, NEDC values will continue to be simultaneously determined until the end of 2020. This will be done either using an EU software tool (CO2MPAS) or based on additional NEDC tests. The CO2MPAS tool was developed by the EU Joint Research Centre. As these converted NEDC values are based, among other things, on the stricter parameters of the WLTP test procedure, they will be higher than in the original NEDC test procedure.
