August 13, 2008

Exclusive tests carried out by 4Car have revealed that so-called 'green' cars are neither as economical nor as planet-friendly as they're made out to be.

Channel 4’s 4Car have run tests on the fuel economy of a number of new cars that throws the veracity all economy figures into disarray.  The models tested were all cars that claim to be eco conscious and they’re all classed in the car tax group B, but if the tests are accurate should be classed in group C, a difference of £85 for annual tax renewal.

The test looked at eight different models the Volkswagen Golf BlueMotion, Skoda Fabia Greenline, Toyota Aygo, Mini Cooper D, Honda Civic Hybrid, BMW 118d, Fiat 500 1.2 and Ford Focus Econetic - all cars claimed to have excellent fuel economy and low emissions.  The model that came closest to being accurate was the Golf Bluemotion, and that was more than 5mpg out.  The Ford Focus Econoetic proved to be 11.6 mpg wide of the mark with 54mpg in the 4Car tests rather than the 65.4 quoted in the cars vital stats.

Under current standardised testing the tests are carried out in a laboratory on cars which have been run-in and driven for at least 1,800 miles. Urban and an extra-urban cycle are tested, with a combined fuel consumption figure then calculated as an average of the two. Exhaust emissions are also measured.

Independent test organisations, manufacturers or importers carry out the tests at their own facilities, but under stringent European Commission directives in order to achieve consistency.

Before the results are officially recognised in the UK, the Department for Transport inspects the test laboratories and witnesses some tests being carried out, or checks that the figures have been certified by a European government.

Details of all the cars’ performances are listed in the table below.

No explanation as to why there is a difference in the amount of error has been offered, but it's hard to believe that the testing is completely standardised if the margin of error varies between 5.5 and 11.6mpg in testing.

In the wake of 4Car’s findings the industry must surely find a new testing model that actually presents accurate figures, figures that are relevant in real driving conditions.  While the cars that were tested all claimed to be fuel efficient and generate low emissions it’s probably fair to assume that other cars fuel figures are also wrong, in which case what is the point in providing the information in the first place?

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