The gap between fuel efficiency numbers published by carmakers and the actual figures has widened after a decade, according to a research by the non-profit International Council on Clean Transportation (ICCT). The research shows that the “real-world” carbon dioxide emissions for new cars based on fuel consumption are around 25-percent higher on average than what carmakers claim, compared with just 10 percent a decade ago.
The research also shows that German premium vehicles had the biggest gap in published and actual fuel efficiency numbers. According to the report, BMW’s emissions figures for its vehicles are on average 30-percent lower than in actual use.
Audi’s emissions figures for its vehicles, meanwhile, are on average 28-percent below actual use. Mercedes-Benz’s emission numbers, on the other hand, are on average 26 percent lower than in real-world use. The report also disclosed that the gap between published and actual emission figures for Toyota vehicles were around 15 percent, and for Renault and PSA/Peugeot-Citroen units were about 16 percent.
Peter Mock, managing director of ICCT Europe, remarked that this means that the actual fuel consumption experienced by the average driver is typically 25-percent higher than what the carmaker claims. The report noted that the difference in fuel use made drivers pay on average an extra EUR300 ($390) yearly. ICCT’s report was based on data from nearly half a million private and company vehicles across Europe.
Prior research has shown how carmakers were able to lower fuel use and carbon dioxide emission in laboratory tests like using tires with extra traction or unrealistically smooth driving surfaces. ICCT’s research is expected to place more pressure for the reform of EU vehicle testing procedures to ensure that advertised fuel-efficiency numbers reflect actual use. This may be bad news for carmakers, since this means that it would be harder for them to meet new EU carbon dioxide vehicle emissions target proposed for 2020.