RAC Cars News


Manufacturers Challenged On MPG Figures

By raccars Published

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There has long been controversy surrounding manufacturers' official MPG claims versus the mileage actually achievable in the real world. European consumer organisation BEUC is now warning that misleading manufacturer mileage claims could be costing car owners £400 per year.

Altroconsumo, an Italian consumer agency belonging to BEUC, recently conducted independent laboratory testing to verify manufacturers' mileage claims. The cars tested were a Volkswagen Golf 1.6 TDI and a Fiat Panda 1.2. VW official figures state that the Golf uses 3.8 litres of fuel to travel 100km, but the best fuel consumption attained in Altroconsumo's tests was 5.83 litres over 100km — a 53.4% discrepancy. Similarly, Fiat claims fuel consumption of 5.21 litres per 100km for the Panda 1.2, but consumer testing revealed results 17.3% higher at 6.11 litres per 100km. Altroconsumo is now working to take the manufacturers involved to court on behalf of car owners, who it claims have been misled into thinking their cars are far more efficient than they really are.

BEUC is frustrated by the current regime used for judging official MPG figures, which has not been updated since the 1970s and allows manufacturers to exploit a number of loopholes in the system. Tricks used by car makers to artificially inflate their vehicles' mileage achievements include over-inflating the tyres. While this can reduce fuel consumption under test conditions by up to 2.9%, it is not a realistic way to drive under normal circumstances. Manufacturers also adjust the way they accelerate and brake during testing to put as little load upon the car's electrical systems as possible. They also use specialist lubricants to reduce engine friction — products which are not usually available to consumers. Fuel consumption can also be artificially reduced in test conditions by taping up gaps between body panels to lower air resistance, while removing interior fittings makes the car lighter.

BEUC claims that not only does using unrealistic testing techniques mean it is impossible for consumers to make informed purchase decisions based upon fuel economy, but it also has a knock-on effect upon tax-band valuations. As these are based upon CO2 emissions in a number of European countries, false fuel consumption figures could mean some cars are being placed into incorrect tax bands.

The consumer agency is now pushing the EU to update the standardised testing procedure currently in use and replace it with a new system adopted by the United Nations this year, so that consumers can gain a clear idea of how much fuel their car will use in real-life driving circumstances.

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