Manufacturers are using loopholes in test procedures to overstate the fuel efficiency of their cars, according to a damning new report from a pressure group.
European data suggests new cars achieve 56.5mpg and emit 127g/km of CO2 on average - meaning they have already met the 2015 target of reducing emissions to 130g/km.
However, the Transport & Environment (T&E) pressure group, based in Brussels, claims the true average fuel efficiency of cars is far lower at 45mpg and the test used by manufacturers is obsolete.
The group's clean vehicles manager, Greg Archer, said makers are using loopholes to distort how economical and environmentally-friendly their cars really are in real-world situations.
The manufacturers say the tests make it easier for car buyers to compare models and are carried out in their laboratories, not in real life.
The T&E claims manufacturers use 'tricks' such as angling the tyres so less of the rubber touches the road surface; reducing wind resistance by putting tape over gaps in panels and keeping gearboxes and engines in optimum order using special oils that reduce friction as much as possible.
New European Commission procedures set to be introduced in 2017 are expected to make tests more representative of the true performance buyers can expect from cars, but the T&E believes manufacturers are trying to delay them until 2021 - after which they will have to pay financial penalties if their new models emit more than 95g/km of CO2 on average.
Copyright Press Association 2014