DRIVERS are spending nearly an extra £300 a year because the gap between cars’ official fuel consumption figures and reality is widening, a report by the International Council on Clean Transportation (ICCT) claimed today.
The Berlin-based independent research group said the disparity had increased from 10 per cent to one quarter over the last decade - reaching the equivalent of an average extra £260 in annual fuel costs.
It found this was greatest among BMW models, which used around one third more fuel than claimed in brochures, followed by Audi and Vauxhall.
ICCT Europe managing director Dr Peter Mock said: “All data sources confirm the gap between sales brochure figures and the real world is growing.
“Our analysis comprises driving data from all across Europe, both private and company cars, all told nearly half a million vehicles.
“If left uncorrected, this growing gap is bound to both increase distrust among consumers of the official numbers and decrease their willingness to invest in fuel-saving technologies.”
He said a new test procedure being finalised should produce more realistic fuel consumption figures. It is due to be introduced in three years time.
Dr Mock said the worldwide harmonised light vehicles test procedure “will be a huge step toward correcting this discrepancy”.
Transport campaigners Transform Scotland accused manufacturers of misleading car buyers.
Director Colin Howden said: “While the European emissions standards are certainly helping to drive down pollution from new cars, this new research shows the claims made by carmakers need to be treated with considerable caution.
“It’s deeply unsatisfactory for cars to be producing up to 30 per cent more pollution than manufacturers advertise.
“It’s particularly telling that the makers of the most polluting brands appear to be misleading consumers the most.
“It would be more useful if they concentrated on making vehicles that cut emissions rather than simply fiddling the figures.”
The Society of Motor Manufacturers and Traders, which represents the UK industry said it was “actively contributing” to the development of the new test procedure.
A spokesman said: “The real-world fuel-efficiency experienced by motorists can vary from driver to driver as it depends on many external factors such as driving behaviour, traffic conditions, terrain, road type and vehicle load.
“Even if two people drive the same vehicle under the same conditions, each will achieve different levels of fuel efficiency.
“Any difference between a fuel consumption and official European figures is the result of the difference between driver behaviour in real-world conditions and the laboratory tests prescribed by legal requirements.”