Carmakers accused of ‘manipulating’ emissions tests

An NGO report claims that ‘lax’ testing procedures allow car manufacturers to manipulate emissions and fuel economy results for their vehicles

Car manufacturers are able to manipulate emissions tests to produce “unrealistically low” results due to “outdated and lax” testing procedures, according to an NGO report.

The report, ‘Mind the Gap! Why official car fuel economy figures don’t match up to reality’, was published online by European NGO Transport & Environment (T & E) on Wednesday (March 13).

T & E has accused car makers of manipulating emissions tests

Transport & Environment has accused car makers of manipulating emissions tests

It shows a growing gap between official New European Driving Cycle (NEDC) test results for nitrogen dioxide and carbon emissions and the typical real-world driving performance of cars in Europe. Drivers are becoming distrustful of official fuel economy data and as a result are less likely to consider buying a more efficient vehicle, the report claims.

Testing cars for emissions levels and fuel economy enables governments to levy the correct levels of vehicle taxes and to make sure regulations to reduce emissions from cars are effective. It also provides consumers with information about the efficiency of their vehicles.


However, car manufacturers are still acting within the formal rules, and as a result, T & E has called for new rules to close the biggest loopholes in the current NEDC test procedures, and to introduce a testing system independent from car manufacturers by 2020.

It states that the current supervision of testing and checks on production vehicles is “inconsistent and inadequate”.

Air conditioning, navigation and media systems, heated seats and other car accessories are not switched on during testing, the report found, which in the real world contributes to higher energy consumption than official test results suggest.

Other tactics used by car manufacturers to manipulate emissions tests take place in both the laboratory and on the road — the two sections of the official EU test — according to T & E. These include: fitting special lower resistance tyres and over inflating them; taping over indentations or protrusions on the vehicle body to reduce aerodynamic drag; and using higher gears to increase the operating efficiency of the engine.

The report states: “These practices are now commonplace, with testing facilities being paid to optimise the results of the tests. 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.”

T & E cites Germany as a typical example, where projections of fuel economy from inaccurate testing are costing drivers €2,000 (£1726) over the lifetime of their vehicle.

It adds: “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.”

The ‘Mind the Gap!’ report is available on the Transport & Environment website.


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