A focal point for motorists dissatisfied with real-world MPG in comparison to the official MPG figures, Next Green Car invites motorists to give their views, sign-the e-petition and Next Green Car will lobby the manufacturers, UK Government and European Commission on their behalf.

Next Green Car’s e-post bag is dominated by comments from buyers of new cars who complain that they can’t achieve the fuel economy claimed by the manufacturer; an issue of particular concern in cases where the ‘official’ MPG figure is the main motivation for the purchase.

“This is the number one issue for our website visitors”, says Melanie Shufflebotham, Sales and Marketing for Next Green Car. “Finding a car with good fuel economy is a central for many new car purchasers and our visitors seem genuinely bewildered when they find the real-world MPG often bears little resemblance to the official figures.”

The central cause of this confusion is the  ‘New European Driving Cycle’ (NEDC) which is used to generate the familiar ‘urban’, ‘extra-urban’ and ‘combined’ official figures. Performed on a chassis dynamometer, these tests are used for emissions certification of light duty vehicles in Europe, and from which fuel economy figures are calculated (rather than measured).

However, not only is the NEDC out of date (cars were lighted and less powerful than they are now), the tests are no longer representative of real world driving, which is now more aggressive. The tests are also conducted with all ancillary loads (such as heating, air conditioning, lights, and heated windows) turned off – air conditioning alone can worsen fuel economy by at least 20%.

In the opinion of Dr Ben Lane, Managing Editor of Next Green Car: “While technologies have moved on, the test procedure is stuck in an 11-mile, 20-minute time-warp, one that is increasingly unrepresentative of real-world driving.”

He continues: “While this appears first and foremost a consumer issue, it should be of more concern to manufacturers. Why? Because it’s an issue of Trust. While car makers are not responsible for designing the NEDC, I believe they should be doing more to improve the test and develop innovative ways to assess and communicate environmental performance. In a spirit of enlightened self interest, they should do this not only as a means of providing better information, but as part of improving customer service.”

Moves are afoot to replace the NEDC, but not until 2014 at the earliest. One option on the table is the Artemis Driving Cycle (ADC) which consists of four drive cycles (urban, rural road, two motorway) all of which include the rapid changes in speed typical of driving on real roads. What’s not yet being considered, however, is an alternative approach to the use of dynamometer testing. With a digital and information revolution going on, testing in the field (as well as in the lab) is now a real option.

While the auto industry’s endorsement of the ‘Best Practice Principles for Environmental Claims’ (by LowCVP, SMMT and ISBA) indicates that the sector is starting to engage with this issue, it is less clear how this endorsement will translate to the showroom floor.

As observed by Dr Lane: Do expect your salesperson to say, “We can offer you a great discount on this model”; don’t expect him or her to say of its fuel economy or CO2 emissions, “It does exactly what it says on the tin”.