YOUR car could be using a lot more fuel than its maker claims, according to a new report.
An official European Commission study says European manufacturers are exploiting test loopholes to make their cars appear "greener" than they are.
The analysis from three consulting firms found that cars can be a good deal less fuel-efficient than their official figures suggest.
For example, using certain kinds of tyres or driving on exceptionally smooth road surfaces during tests could push down fuel consumption by significant amounts.
There appear to be numerous grey areas in supervision and accountability. The report's claims suggest there is a marked difference between the spirit and the letter of the law on fuel consumption reporting.
The European Commission is revising the testing laws but experts do not expect this to close all the loopholes.
According to a report in 'Automotive News Europe', the use of extreme conditions to boost fuel consumption could account for about a third of the recorded drop in average carbon dioxide emissions in the EU between 2002 and 2010.
It quoted an unnamed EU source as saying: "The industry is running rings around this procedure."
EU consumer organisation BEUC calculates that the "flexibilities" in testing mean annual fuel bills could be €135 more in fuel for those driving an average of 14,000km a year.