Research shows official fuel consumption claims are off by miles, with many drivers getting 25% less than promised
Car buyers are being misled by fuel consumption claims, according to research revealing some vehicles, including top makes such as Mercedes, Range Rover and Lexus, get as little as 71% of the advertised mileage per gallon.
Manufacturers increasingly claim in adverts that their cars will manage over 70mpg. However, a major survey of what cars are achieving on the road, by motoring website HonestJohn.co.uk, found that many drivers are getting less than three-quarters of the mpg they had expected. It estimates that overstated official fuel figures are collectively costing UK drivers up to £4.4bn a year in extra costs.
The motoring website invited drivers to submit how many miles their cars actually do to the gallon. More than 30,000 responded, covering all major manufacturers and models – and the majority failed to meet official figures. On average, cars achieve only 88% of their official figures, Honest John found, forcing drivers to spend around an extra 2p a litre every time they fill their tanks.
The worst-performing car was the Mercedes Benz B-Class (2005-12), which drivers report achieves 71% of its official fuel economy rating. The Range Rover Evoque and Lexus CT200h come a close second and third, achieving 73% and 73.6% respectively.
The Audi A1 fares little better, managing on average only 46.8 miles to the gallon. The current Vauxhall Astra Sports Tourer achieved 74% of its recorded fuel economy, with no driver managing more than 55mpg compared with the 70.6mpg the manufacturer officially claims.
The findings chime with Guardian Money readers’ experiences. Several have contacted us in recent months to complain that their new car is using far more fuel than they had expected. While poor driving styles will account for some of the discrepancy, many owners believe their vehicle will never achieve the official figures.
However, it wasn’t all bad news. The survey reveals that some cars actually post figures that are better than claimed. The Land Rover Defender achieves 105.1% of its official test result, and the Jaguar S-Type also exceeds expectations, achieving 3.6% better than official figures.
The Nissan Micra (2003-10) and the Mercedes-Benz E-Class (2002-2009) finish third and fourth, achieving 102.7% and 102.1% of their official fuel economies, while the Honda Civic Type R (2007-2011) comes a close fourth with a real mpg ratio of 102.1%.
Honest John says: “The official figures, which could be said to mislead consumers, are the only figures car manufacturers are allowed by EC law to publicise. Rather than attack the EC figures, we prefer to offer realistic figures achieved by real motorists to be used alongside official guidelines. Consumers will be now able to compare official figures with user experience, helping them to make better informed decisions about their next purchase.”
A spokesman for the Society of Motor Manufacturers and Traders says cars have become 25% more fuel efficient over the past decade. “This information demonstrates the significant impact that drivers and road conditions can have on a car’s fuel efficiency. The results add to a range of tools that can help advise motorists choose the most appropriate vehicle, engine and fuel type for their needs. It is important that the industry continues to provide the legally-required data through globally repeatable tests, under laboratory conditions, to ensure consistency and comparability.”