Environment and Climate

Global WLTP roll-out for more realistic results in fuel consumption

Questions and answers regarding the new international test procedure: Lawmakers require standardized test procedures to measure how much fuel a car consumes and whether it complies with the emissions limits. The new “Worldwide harmonized Light-duty vehicles Test Procedure” (WLTP) will apply to the type approval of new passenger cars across the EU since September 1, 2017. It will succeed the NEDC (New European Driving Cycle), which has been in force since 1992. It comprises both a new driving profile on test benches as well as more precise and up-to-date conditions for the entire test and is therefore intended to result in more realistic consumption data. What are the implications of the change? Seven questions, seven answers.

What does the WLTP mean for motorists?

Even though the WLTP cannot depict the full range of actual vehicle usage, it provides a better basis of information for making decisions when buying a car by providing a greater approximation to real-world driving conditions. In order to be able to compare vehicles of all manufacturers in the legal transitional period from one test procedure to the other, the European Commission recommends a uniform revision of published information for customers and consumers in the EU as of January 1, 2019. The corresponding “Regulation for Energy Consumption Labeling” applies to the implementation schedule in Germany.

A car’s fuel consumption is not constant, but dependent on driving style, weather and driving distance. Other important determining factors include whether winter tires have been fitted, the air conditioning is running at full speed or holiday luggage is on board. Nevertheless, car buyers understandably want fuel consumption data that is as exact as possible. This data must have been produced under absolutely objective and reproducible measuring conditions in order to be able to compare vehicles from different manufacturers. Furthermore, the declared fuel consumption should be as realistic as possible in order to make an accurate estimate of the operating costs arising after purchase. Yet even the WLTP will not be able to reflect the full range of actual vehicle usage. However, the new test procedure, while retaining objectivity, reflects real-world driving considerably better than the previous statutory driving cycle and thus provides a better basis for purchasing decisions.

Not yet finalized is the question as to when all car dealers in Europe will be able to declare the emission values determined according to the new procedure. The EU member states decide independently when WLTP values may or must be displayed. In order to ensure comprehensive comparability even when the first post-WLTP certified vehicles are on the market, the EU Commission recommends to its member states a uniform revision of published standard values as of January 1, 2019. In Germany, the cut-off date for this revision is determined by the statutory change in the “Regulation for Energy Consumption Labeling.” The German Federal Government has not yet defined this cut-off date.

Since the differences between the test bench results and actual fuel consumption will continue to exist, car manufacturers are currently conducting a detailed evaluation as to whether it may be appropriate to offer new car buyers – in addition to the WLTP value – customer-specific fuel consumption figures on a voluntary basis in the future. This way it would be possible to offer transparent information on the fuel consumption range of a particular vehicle. This range of anticipated customer-specific consumption to be declared depends on various factors such as driving style, route profile, climatic conditions or air conditioning usage. In this context, one possible idea is the establishment of an institute that could determine and declare this consumption range in the role of a voluntary body and in cooperation with testing organizations.

In many member states of the European Union, vehicle CO2 emissions are also the basis for calculating the amount of vehicle tax, duties or incentives. Defining these kinds of financial instruments is the responsibility of national governments. Since the CO2 values according to the WLTP test procedure are higher than according to the old NEDC standard, the tax rate for Germany’s motor vehicle tax would actually have to be reduced by 20 percent as it is calculated based on the unit of “grams of CO2 per kilometer”. However, the revision of the vehicle tax has already been decided for all newly registered vehicles as of September 1, 2018, without such an adjustment, which will be equivalent to a tax increase.

The higher WLTP values must also be taken into account when classifying vehicles into so-called efficiency classes, which are declared at the retail level and in internet configurators. The following applies to the requirements in Germany: which class a vehicle is assigned to, ranging from A+ (green = very efficient) to G (red = less efficient), depends on how much its CO2 emissions deviate from a reference value that applies to equally heavy vehicles. Since the reference value is still based on the old NEDC, while the WLTP cycle now produces higher standard values, a vehicle would now automatically be classified into a poorer efficiency class without any adjustment to the reference value – even though its actual fuel consumption will, of course, not change on account of the new test procedure.

If and when lawmakers will adjust the reference value upwards is currently unknown. What is certain, however, is that there will be no ambiguities for German customers who want to compare the consumption values of different vehicles, e.g. when purchasing a car. As with the declaration of emission and consumption values, there will also be a fixed cut-off date for labeling from which all updated efficiency classes will be declared across Germany. This cut-off date for the revision has not yet been finalized by the German legislature. Since EU states decide on these cut-off dates autonomously, models will be labeled differently across different countries for a transitional period.

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