Report: Car emissions higher than predicted

Current test rules show inaccurate fuel consumption and pollution levels. [Kevin Dooley/Flickr]

Cars are not as fuel efficient and environmentally friendly as officially described by the carmakers, a Transport and Environment (T&E) report has found. The reality is different due to flaws in the testing system.

The T&E report, 2014 Mind the Gap, compared the results of cars tested in a laboratory and in an everyday life environment. The assessment showed that the pollution and consumption levels for cars on the test site are higher than initially specified by their manufacturers.  

“On average, across all car brands, the gap between real-world fuel consumption and carmakers’ claims has widened from 8% in 2001 to a staggering 31% in 2013 for private motorists,” said T&E.

“The additional fuel burned compared to official test results costs a typical driver €500 a year.”

The automobile industry relies on the New European Driving Cycle (NEDC) test, a standardised EU legal procedure, to compare the performance of different cars in similar conditions.

But as the test takes place in a laboratory, the outcome does not take in consideration the influence of external factors, such as road type, weather or traffic conditions.

“Any difference between customers’ individual fuel consumption and NEDC figures is the result of the difference between drivers’ behaviour in real-world conditions on the one hand, and laboratory tests prescribed by legal requirements on the other,” said the European Automobile Manufacturers’ Association (ACEA).

NEDC, according to T&E, is obsolete, “unrepresentative of modern cars and driving styles, and full of loopholes that carmakers exploit to produce better test results”. 

EU carmakers have been using NEDC since 1996, as a regular procedure to test cars before being authorised for sale. Even if the cars’ characteristics have evolved in the past few decades, the assessment requirements stayed the same.

“All carmakers optimise test results, but data from Spritmonitor shows that cars produced by Daimler, BMW and Ford exhibit the largest real-world gaps – in excess of 30%,” said T&E.

Under NEDC, some of the loopholes mentioned in the report include specially-built cars for laboratory tests in order to perform better. Or an engine system that will be able to detect when a car is tested in order to deliver better fuel-efficiency results.

The findings also show that smaller automobiles are not as fuel efficient as initially thought. For instance, a car engine size below 1 litre in size will have higher emissions than those with an engine of 1-2 litres. 

“This shows that carmakers appear to be manipulating test results in order to place cars in the lowest tax bands,” said the report.  

The European Commission will replace the old standard procedure with the Worldwide Harmonised Light vehicles (WLTP). The new test is meant to measure more accurately cars’ performances and is expected to be applied only as of 2017. 

“The automotive industry […] is actively contributing to the development of the new global test cycle WLTP, which is designed to represent more closely real-world driving,” said ACEA.

The T&E report has based its findings on the International Council on Clean Transportation (ICCT) research. ICCT has analysed half a million cars to compare real-world fuel economy in Europe with the official test results. 

Road transport contributes about one-fifth of the EU's total emissions of carbon dioxide and is the only major sector in the EU where greenhouse gas emissions are still rising.

The European Union adopted legislation that will help reduce the emission targets for new cars. 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 - and 95g/km by 2021, phased in from 2020. The 2015 and 2021 targets represent reductions of 18% and 40% respectively compared with the 2007 fleet average of 158.7g/km. In terms of fuel consumption, the 2015 target is approximately equivalent to 5.6 litres per 100 km (l/100 km) of petrol or 4.9 l/100 km of diesel. 

Transport & Environment

  • Report “2014 Mind the Gap: manipulation of fuel economy test results by carmakers” 

European Automobile Manufacturers' Association

  • Statement "Contributing actively to the development of a new test cycle"


Subscribe to our newsletters