In road tests carried out by Auto Express magazine, cars promoted as environmentally friendly performed so badly that their green credentials were dismissed as a gimmick, pumping out up to 56% more carbon dioxide than manufacturers claim.

The Honda Civic hybrid, regarded widely as one of the lowest emitting cars, performed the worst in the tests. Instead of the 109g/km of CO₂ claimed in the makers' specifications, it was found to put out 171g/km. The testers said its electric motor was "not strong enough to propel the oddball four-door Civic on its own" and that the vehicle "failed to match the firm's economy claims".

David Johns, the magazine's editor, said that demand for eco-friendly cars was on the rise but it could be hard for consumers to determine what was "truly green or just pure gimmick".

Almost a quarter of new cars now claim to produce less than 140g/ km CO₂ emissions. Those with a figure below 120g/ km accounted for one in 20 sales last year, though it is thought that this figure would have been higher, given a better supply.

Along with the Honda Civic hybrid, the Lexus GS450h (leased for testing by David Cameron, Conservative Party leader) also had its green credentials trampled on. The manufacturers claim that this car will do 35.8 miles per gallon. In the road test however it managed just 26.7 mpg, meaning higher carbon emissions. It has been said that diesel rivals "produce similar emissions and better economy".

Despite fuel consumption, the testers listed five cars as able to be considered green because of the technological innovations used to reduce CO₂ emissions. These were the Ford's Focus ECOnetic, the Mini Cooper Clubman D, VW Polo BlueMotion, Seat Ibiza ECOmotive and Toyota Prius.

Official figures for cars are based on laboratory tests conducted by the manufacturers themselves, importers or independent test engineers, and not actual road tests. A spokesman admitted that cars may emit more CO₂ under real world operating conditions but insisted that all cars had the same "industry standard" tests - the results of which clearly bear no relation to road performance.

The Society of Motor Manufacturers and Traders however, did insist that the industry had "made progress in delivering lower carbon cars".

Posted under Articles, Environmental News