Car makers shown to fix official MPG data

A new report provides compelling evidence on why there is a growing gap between the official fuel consumption and CO2 emissions of new passenger cars, and that which is achieved by the same vehicles on the road.

The report by the European NGO Transport & Environment (T&E) demonstrates that the current New European Drive Cycle (NEDC) test is outdated and unrepresentative of real-world driving, and that lax testing procedures are allowing car-makers to manipulate the official tests to produce unrealistically low results.

The report also shows that the current supervision of testing and checks on production vehicles (to ensure these are equivalent to tested vehicles) are inconsistent and inadequate, with manufacturers paying the organisations undertaking and certifying the tests. The conclusion is that the current system for measuring car and van fuel economy and CO2 emissions is not fit for purpose and is in need to urgent updating.

Providing reliable information about the fuel economy of cars is important as it helps car buyers choose models with lower running costs (fuel and car tax). Having accurate tests of vehicle carbon dioxide (CO2) emissions is also essential to enable governments to levy the correct level of vehicle taxes and ensure regulations to reduce emissions from new cars are effective.

However, as often reported on Next Green Car – see MPG Monitor – most drivers know that it is usually impossible to achieve the official manufacturer fuel efficiency figures, and for some individual models, the report finds that real-world emissions are now up to 50% higher than the test results.

The report also gap between official test results and typical real-world driving performance is growing and cites the following three reasons:
1. The current test is unrepresentative of real-world cars and driving. Much of the technology introduced to improve efficiency of cars is far more effective in the test than on the road. For example, technology to switch off the engine when the vehicle is stationary is very effective during the test when the vehicle is stationary for 20% of the cycle;
2. Cars are also increasingly fitted with energy-guzzling accessories like air-conditioning, navigation and media systems, heated-seats, etc. This equipment is not switched on during the test and by omitting the energy consumed, the official test results are lowered;
3. The current (NEDC) test procedures are outdated and lax and contain many loopholes that carmakers are increasingly exploiting to lower the results.

The T&E report provides details of how car makers manipulate the official MPG and CO2 figures. In the first half of the test, during which the air and rolling resistance of the car is measured, it is now commonplace for carmakers to adjust the brakes, pump up the tyres, and tape up all the cracks around the doors and windows to reduce the air and rolling resistance. While there is no evidence that carmakers are breaking any formal rules, the current test procedures are so lax there is ample opportunity to massage the test results.

Results are also being over stated in the second stage of laboratory tests during which the car is driven on a rolling road through the NEDC test cycle comprising a series of accelerations, steady state driving and decelerations. This is achieved, for example, by disconnecting the battery during the test, minimizing the weight of the car, using special lubricants that are not supplied with the production vehicle and testing in unrealistically hot temperatures. The current procedure also inexplicably allows the CO2 results declared by the manufacturer to be up to 4% below the measured results.

Independent tests conducted using the official drive cycle but with regular production vehicles and without using all the loopholes in the rules, produce results for CO2 emissions and fuel consumption which are 19%-28% (average 23%) higher than the official figures reported. About half of this is explained by differences accruing from the road load testing, the other half comes from differences in the laboratory testing.

The extent to which manipulation of the tests has contributed to the improvement in official CO2 figures has also been estimated by consultants for the European Commission. They conclude around 30% of the net CO2 emission reduction over the last decade does not result from technology deployment and that â€Å"utilisation of flexibilities may account for two-fifths to one half of the net CO2 emission reduction between 2002 and 2010.”

The T&E report makes four recommending to address the current distortion of car fuel economy and CO2 measurements in official tests and to ensure the system is robust and fit for purpose:
1. New rules should be introduced to close the biggest loopholes in the current (NEDC) test procedures. This should be followed by re-testing of all current production vehicles using the revised procedures to ensure official figures are a better reflection of actual CO2 and fuel economy information. Re-testing should be completed by the end of 2014 to ensure 2015 regulatory targets for new car CO2 levels cannot be distorted by manipulating test results;
2. A new test cycle and testing procedures should be introduced in 2016. The World Light Duty Test Cycle (WLTC) is under development and is expected to be finalised in 2014, providing a modern credible alternative to the current NEDC system. This should be done in a way that ensures the new cycle is representative of typical average driving in the EU and that vehicles are tested under representative conditions, including switching on during the test all equipment such as the lights, air conditioning, etc.;
3. By 2020, a new system for type approval of vehicles should be introduced to ensure certifying and testing bodies are entirely independent of carmakers. This should include specific consideration of establishing an EU-wide Type Approval Authority that would then sub-contract testing services to accredited national organisations;
4. The car labelling directive should be reviewed in order to restore consumer confidence, on the basis of the US model that communicates the best possible estimate of real-world fuel economy.

The report therefore provides timely and compelling evidence that carmakers are currently misleading their customers by promoting fuel efficiency figures that they know will not be achieved. Carmakers are also cheating policy-makers by manipulating the official tests and producing vehicles that only achieve regulatory targets during the test; not on the road where the fuel is burnt and emissions occur.

Next Green Car comment

Next Green Car fully supports the aims, findings and recommendations of the T&E report. As we have highlighted in our MPG Monitor campaign, car buyers are increasingly mistrustful of official MPG figures. We think this is undermining the normally excellent relationship between car manufacturers and their customers, one that needs to be protected through the exchange of high quality and accurate information.

Dr Ben Lane, Managing Editor of Next Green Car said of the T&E report: "This is really important and timely research that adds quantitative evidence to what most drivers know from their own experience. The reason it is so crucial is that many car buyers are trying to do the 'right thing' by buying cars with high fuel economy, both to cut fuel costs and to reduce carbon emissions. But if the information is less accurate that it should be, how are consumers to make the best purchasing decisions? What is more, if we believe the official figures, we are kidding ourselves about the success of our efforts to address climate change. The car industry can do better than this – and in time I believe it will."

Next Green Car also agrees that an updated system is urgently required to ensure that car tax, which is now closely linked to official CO2 data, will be more effective in driving the shift to more fuel efficient models as supported by the EU CO2 regulations requiring emissions from cars to reduce over time. If the loopholes identified by T&E are not closed, the environmental and the wider economic benefits of low CO2 incentives and regulations will be much smaller than would be expected, which in turn will adversely impact upon the growing UK low carbon vehicle industry as well as climate change, an issue that will increasingly affect us all.

Note: While Next Green Car uses the official MPG figures as part of its data set, research shows that the MPG data remains useful for fuel economy comparisons between different models. In response to the T&E report, NGC will be adding 'Real MPG' estimates for all vehicles in its 30,000 strong database from April 2013.

Download the T&E Report: Mind the Gap! [2.5MB]


Ben Lane

Author:Ben Lane
Date Updated:18th Mar 2013

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