Fuel economy claims costing drivers an extra €450 a year at the pumps

The gap between claimed and actual fuel consumption has ballooned in the past decade

Car makers are being effectively encouraged to ’cheat’ the fuel economy test by stricter Co2 limits

Car makers are being effectively encouraged to ’cheat’ the fuel economy test by stricter Co2 limits


European motorists are spending €450 per year more for fuel than they might expect to pay, because of exaggerated economy claims by carmakers.

These claims have hit the headlines in recent days, as an Italian consumer organisation, Altroconsumo, is planning to take both Fiat and Volkswagen to court, saying that they overinflated claims for the fuel consumption of their Panda and Golf models.

Fuel will be added to Altroconsumo’s fire thanks to research by the International Council on Clean Transportation (ICCT) that shows the gap between claimed and “real-world” fuel economy has ballooned from about 10 per cent a decade ago to an enormous 30 per cent now.

The new report, jointly prepared by the ICCT, the Netherlands’ Organisation for Applied Scientific Research (TNO), and Germany’s Institut für Energie-und Umweltforschung Heidelberg (IFEU), unveils the increasing real-world efficiency gap using systematic statistical analysis.

Real-world gap


The analysis draws on data from a number of sources: the user websites spritmonitor.de (Germany) and honestjohn.co.uk (UK), leasing companies Travelcard (Netherlands) and LeasePlan (Germany), the German car and consumer magazines Auto Bild and Auto Motor Sport, the UK’s WhatCar? and the Swiss car club TCS. “Our analysis comprises on-road driving data from all across Europe, both private and company cars, all told nearly half a million vehicles” says Dr Mock.

While the extra €450 annual cost in fuel bills is a bitter enough pill to swallow, there are potential knock-on effects of research such as this, which could have wide-ranging implications for both the motor industry and its consumers.

ICCT points out that the increase in the discrepancy has come about at a time of ever stricter emissions legislation.


Environmental pressure group Transport & Environment agrees with this assertion, saying in a statement that “between 2000 and 2007 emissions of the average new car (as tested on the standard test procedure) dropped by just 1.2 per cent per year, on average. Since legislation was first announced in 2007, the average rate of progress has been four per cent a year. It is also clear that a significant part of this improvement has been achieved though manipulation of the current test procedures to produce artificially low results. The tougher the regulation gets, the bigger the incentive for exploiting the flexibilities becomes.”

Governments are also losing out. ICCT points out that the gap between the test and the observed figures is currently costing the government of the Netherlands a potential €3.4 billion every year.

As has been previously pointed out, the replacing of the current New European Driving Cycle (NEDC) with the UN’s Worldwide Light Vehicle Test Procedure (WLTP) would limit carmakers’ options when it came to optimising their cars for the test.

Currently, such “cheats” as blocking off aerodynamic gaps with tape, removing heavy items such as spare wheels, filling the engines with extra-low viscosity short-life oil and disconnecting such power-sapping items as the alternator are all overlooked.

The WLTP would eliminate much of this, and while it has been proposed for European introduction in 2017, the major carmakers are resisting it at every turn, not least because there is a new, strict, 95g/km average carbon-dioxide limit to hit by 2020.

“The new test procedure will fix a number of flaws in the current procedure, and it should be introduced in the European Union as quickly as possible,” says Dr Mock of ICCT.

“It will not resolve all the open issues, but it will be a huge step toward correcting this discrepancy, which poses an increasing risk to efforts to make the European car fleet more energy efficient and less polluting.”