Cleaner and cheaper cars

We must close the gap


If no measures are taken, the gap between official and real fuel consumption figures will grow wider than the average of 42% it has already reached.


As of 2017, the CO2 emissions of new cars are to be determined according to a new, globally harmonized process, the Worldwide Light-duty vehicles Test Procedure (or WLTP) ⓘ.

The change to WLTP is a step in the right direction. It will bring more transparency during the tests and therefore cleaner cars.


But even with the WLTP, manipulations cannot be excluded. A sustainable solution requires additional measures:

  • Control of the car parameters specified by the manufacturer (such as the mass or the rolling resistance).
  • Appointment by national governments of official bodies to do independent inspections of the cars already on the road and check their actual fuel consumption. Tested vehicles should be selected on a random basis from stock, as well as after suspicions of wrongdoing. In the case of a relevant deviation, the official fuel consumption values should be corrected. This is already common practice in the USA where the Environmental Protection Agency (EPA) compels car manufacturers to correct their data when deviations of more than 4% have been detected. The EPA also publishes information on the frauds it has detected and calls for fines up to a three-digit million amount.
  • Obligation to provide private drivers, fleet operators and media with realistic fuel consumption figures, the ones obtained by using PEMS for example.
  • Appointment of an official body to which car buyers can apply in the case of fuel consumption deviations they have detected and which gives them legal advice. In Germany for instance, according to a landmark decision of the Federal Court of Justice, every car owner with a proven increase in fuel consumption of more than 10% can demand that the car is repurchased and compensation paid.
  • The shift to the WLTP is a step in the right direction, but will only deliver actual results if politicians enact ambitious 2025 CO2 targets. In order for European and national decision makers to drive emissions down on the road, a real driving emission check has to be conducted.


A shift to the WLTP is a good start. But to effectively tackle global warming and protect consumers, it has to be enforced by checks conducted in parallel. That way, vehicles will be cleaner and cheaper, on the paper as well as for real.