Car manufacturers ‘manipulating fuel efficiency tests’, report says


Drivers who find that the fuel efficiency in their new car doesn't match up to the claims made by the manufacturer, now know it is not their driving to blame. A new report reveals that carmakers routinely manipulate official UN-backed miles/gallons tests, with a series of tricks including stripping the car down to weigh as little as possible, overinflating the tyres and testing in the thin air at high-altitude tracks.

The tricks of the trade are listed in a report by the Transport & Environment campaign group (T&E), which suggests the official fuel consumption cited by car manufacturers is on average almost 25% lower than that achieved in reality, and in some cases 50% lower.

Among the 20 creative but legal ways European carmakers exploit loopholes and boost official performances are: taping over cracks around doors and grills to minimise air resistance, using special super-lubricants, stopping the car's battery recharging, adjusting the wheel alignment and brakes, and testing at unrealistically high temperatures and on super-slick test-tracks.

Greg Archer, clean vehicles manager at T&E, says: "This new evidence shows that carmakers in Europe are cheating their own customers by manipulating official tests, which leads to thousands of euros of additional fuel costs for drivers.

"They are also cheating legislators, as EU laws intended to reduce CO2 emissions from cars and vans are only being met in the laboratory, not on the road. The only way to rebuild this trust is by closing loopholes in the current test procedures, to ensure that cheaters never prosper."

New tests which reflect better modern driving conditions are expected to be introduced to Europe in the next few years. But carmakers are said to be trying to delay their introduction.

The official mileage test, called the New European Driving Cycle, was set up 30 years ago and is administered by a UN subsidiary body called the World Forum for Harmonization of Vehicle Regulations (WFHVR). It is supposed to represent the typical usage of a car in Europe. But, T&E's report found, lax testing procedures are allowing carmakers to manipulate the official tests to produce unrealistic and flattering results.

T&E's report said: "Testing and checks on production vehicles are inconsistent and inadequate, with manufacturers paying the organisations undertaking and certifying the tests." It added that, when the tests were introduced, "no one expected carmakers to adjust the brakes, pump up the tyres, and tape up all the cracks to reduce the air and rolling resistance. These practices are now commonplace, with testing facilities being paid to optimise the results of the tests."

It concluded: "There is no evidence that carmakers are breaking any formal rules – but they don't need to – the current test procedures are so lax there is ample opportunity to massage the test results."

The Society for Motor Manufacturers and Traders said in a statement: "We support enhancements to the test procedures and are contributing to the development of a new test cycle [which is] designed to better represent real-world driving." The SMMT said the mileage data was "prone to error" because "a limited number of vehicles" were tested, but added: "Vehicle manufacturers carried out more than 3,500 independently verified tests in accordance with detailed legal guidelines set out by the European Commission. Each model received an initial test, which is followed by random monitoring of the same types of vehicle as they leave the production line, taking the overall test numbers into the tens of thousands."

Raw mileage and emission data is not made public by European carmakers, who only advertise combined figures of laboratory and other tests done on new cars. T&E says it obtained the data on the condition it did not identify the models or manufacturers. Data in the report for the "real world" driving by the public was obtained from online fuel mileage calculators and databases, including, which allows drivers to compare their experiences with million of others.

Furthermore, testing undertaken for T&E by an independent laboratory found that older vehicles performed on average 19% worse in real world conditions than the results obtained in official tests. For newer models the average difference was 37%.

"By creative interpretation of the test procedures carmakers are able to achieve multiple small improvements that lower the test results," the report said. It added: "The current procedure also inexplicably allows the CO2 results declared by the manufacturer to be up to 4% below the measured results." The WFHVR, based in Switzerland, did not respond to requests for comment.

Peter Mock, managing director of the International Council on Clean Transportation Europe, told EURACTIV: "The current test procedure has quite a few flexibilities but that was not a problem in the past because this whole system was not meant to measure CO2 emissions. CO2 didn’t cost anything to the manufacturers then but now it can be very valuable and if you can reduce it by exploiting these flexibilities, it will save you money in the end. That’s why manufacturers are using these 'loopholes' more and more. This change over time, the increasing use of flexibilities, is the real problem. It is dangerous as we think we are meeting CO2 targets and in fact we’re not. We just meet them on paper.”

Mock added that the use of loopholes by some manufacturers encouraged others to follow suit. “There is a certain pressure because if others are exploiting those flexibilities you’d better do so too or your numbers will look bad - or you’ll have to invest more in technologies that really bring down CO2 levels, which are usually more expensive than just optimising your vehicle testing.”

Transport and Environment’s clean vehicles manager, Greg Archer, told EURACTIV that car manufacturers currently had many incentives to juke the stats. “The reality is that the industry has been increasingly manipulating these tests in order to provide cars which are taxed at lower levels and therefore more appealing to their customers, and also to achieve their regulatory targets while investing the minimum they need to. They need to accept that the current practices have to stop.”

T&E is calling for vehicles already on the road to be re-tested using more realistic conditions, Archer said, and for a revision of practices allowing car-makers to pay national type approval organisations to conduct their fuel efficiency tests.  

“The car manufacturers’ behaviour at the moment is unethical and involves trickery and sharp practices,” he continued. “They are certainly breaching the CO2 from Cars regulation’s spirit. The regulation is being met in tests but not on the roads so the anticipated CO2 savings are not being realised in practice. The solution is fairly simple. There is a new test cycle which is being developed and should be completed later this year or early next year. It needs to be introduced as soon as possible.

“The Commission proposed introducing it in 2017. We would prefer it a little quicker. But the car industry is arguing very strongly at the moment that the existing test procedures should be maintained until 2021 even though their engineers are working in Geneva to finalise the new one’s details. That can only be happening because they know that the new procedures are much more robust and prefer to work with the old system that is open to manipulation.”

In 2007, the EU proposed legislation setting emission performance standards for new cars, which was adopted in 2009 by the European Parliament and the EU Council of Ministers. Under today's Cars Regulation, the fleet average to be achieved by all new cars is 130 grams of CO2 per kilometre (g/km) by 2015 – with the target phased in from 2012. 

The regulation is currently working its way through the European legislature in order to implement a further target for 2020. Proposals published in 2012 set a goal of 95g/km for new passenger cars by 2020, and 147 g/km for vans. By the end of 2014, new targets could be announced for 2025 and 2030.

Additionally, a White Paper on Transport, presented by the Commission in February 2011, flagged measures to raise the €1.8 trillion which the EU says is needed for infrastructure investment in the next 20 years.

  • 24 April 2013: European Parliament’s environment committee to vote on CO2 in cars proposals
  • May 2013: European Parliament committee vote on CO2 in Vans
  • 2014: Proposed deadline for EU decision on 2025/2030 targets
  • 2015: 130 grams of CO2 per km target to be enforced across Europe
  • 2020: Proposed deadline for 95g/km target for cars
  • 2025: European Commission could impose another milestone on the road to decarbonsiation by 2050
  • 2030: European Commission could impose another milestone on the road to decarbonsiation by 2050

Subscribe to our newsletters