Real-world Fuel Tests Undermine 'Green' Car Claims

AUTO CENTRAL - August 12, 2008: Current tests used by car makers to determine official fuel economy and carbon dioxide emissions don't provide accurate information for buyers, according to new tests carried out by Channel 4’s motoring website 4Car.

4Car carried out real-world fuel economy tests on eight low-emissions cars and all failed to meet the official figures. Three cars were as much as 10mpg short of the published fuel consumption rates.

The tests examined the Golf Bluemotion, Skoda Fabia Greenline, Mini Cooper D, Honda Civic Hybrid, Toyota Aygo, Ford Focus Econetic, Fiat 500 1.2, BMW 118d, all of which are regarded as low emissions/fuel economy models.

The Golf Bluemotion got closest to its official figures in the 4Car tests, achieving 57.5mpg, only 5.3mpg short of the 62.8mpg return in the government-approved tests. Ford's special low-emission version of its best-selling Focus, the Econetic, returned 54mpg in the 4Car tests – 11.6mpg less than the official figure.

The fuel tests also revealed that claimed carbon dioxide emissions figures are unrealistic and that all the cars, which are currently in VED Road Tax Band B, should fall into Road Tax Band C.

The tests were carried out under strict conditions in order to achieve consistency. Unlike the official testing regime, which is carried out in a laboratory, 4Car’s tests were conducted on the road to replicate ‘real world’ driving conditions. And unlike the official figures, which simply combine urban and extra urban cycles, 4Car carried out five sets of tests to arrive at an overall consumption figure.

4Car editor Tim Bowdler said: "The official test regime is too simplistic to embrace all the vagaries of real-world operating conditions and it allows certain types of car to look good – too good in fact.

"The batch of cars that we tested all claim to have ‘green’ credentials, but they are not as environmentally friendly or as economical as we've been led to believe.

"Manufacturers argue that the official tests offer a level playing field that enables potential car buyers to make direct comparisons, but they bear little relation to real-world driving. The official figures are misleading and I can’t see manufacturers calling for a change because they know the current tests make their cars look more fuel-efficient and cleaner than they are."