Mercedes is the leader at manipulating the way vehicles are tested, producing official fuel economy figures in labs that cannot be replicated in the real world, according to a report by Transport & Environment.
The report analyzes real-world fuel consumption by motorists that highlights the abuses by carmakers of the current tests and the failure of EU regulators to close loopholes.
On average, across all car brands, the gap between real-world fuel consumption and carmakers’ claims has widened from 8 percent in 2001 to 31 percent in 2013 for private motorists. The gap for company car drivers averages 43 percent.
Half of the official fuel efficiency gains made since EU laws were adopted in 2008 are not true. For Opel/Vauxhall cars, made by General Motors, less than 20 percent of the measured improvement in the past five years has actually been delivered on the road.
The report notes that the current fuel efficiency test is unrepresentative of modern cars and driving styles and contains loopholes that carmakers exploit to produce better test results.
A new, more realistic and robust global test, the Worldwide Harmonized Light Vehicles Test Procedures, is scheduled to be introduced in 2017, but EU countries have been indecisive in confirming the date – under pressure from carmakers that want to be able to keep exploiting the loopholes in the current test rules until at least 2022.
Cars are responsible for 15 percent of Europe’s total CO2 emissions and are the single largest source of emissions in the transport sector. Nonetheless, in October of last year, EU environment ministers — bowing to pressure from Germany — agreed to change a draft law to cap emissions from cars.