Over the past decade, the way that government agencies measure the emissions from new cars has become increasingly discredited. The discrepancy between readings taken in laboratories under the NEDC test and real-world emissions was initially thought to be around 15-20%, but recently the laboratory results have been shown to underestimate real-world emissions by around 40%.
Since 1 September, the NEDC has been replaced by the RDE (Real Driving Emissions) test for NOx emitted from diesel engines and particulate matter from petrol engines. The RDE test measures emissions in real-world driving conditions using a portable emissions monitoring system. Also on 1 September, the World Light-Duty Test Protocol (WLTP) came into effect – this measures CO2 emissions from cars and vans. It is a considerable improvement on the NEDC test, but is still a laboratory procedure which T&E believes measures emissions 23% lower than they are in reality.
T&E’s clean vehicles director Greg Archer said: ‘There are two central issues here. Firstly, if the EU is setting emissions reduction targets, we have to know that the official data for new vehicle emissions is really being delivered on average, on the road. If not, the car industry will deliver their targets by cheating the new test. Secondly, car companies and government agencies are misleading car buyers by underestimating how much they will have to pay to drive their cars. That’s why accurate data is essential, and the cheating we have seen is such a scandal.’
In a separate development, the French car maker PSA (Peugeot-Citroën), the French NGO FNE, T&E and the certification agency Bureau Veritas have published the results of an 18-month observation of 60 vehicles over 430 road tests covering more than 40,000km. The initiative has led to a detailed report on real-world fuel consumption, and a test protocol that can be used for other vehicles.
Among the report’s findings are that the average car consumes 1.74 litres more fuel per 100km driven than type approval figures suggest (5.8 litres as opposed to 4.06). This means the underreporting of real-world emissions in official published data is 43%, and also means a motorist who drives 10,000km a year in an average car will have to buy 174 litres a year more than the carmaker claims, which by current fuel prices costs about €250 a year.
Archer added: ‘These results show there are realistic and reliable ways of ending the emissions cheating scandal. The fact that a leading carmaker was willing to work with two NGOs and a certification agency shows a willingness among part of the automotive industry to fight the emissions problem and work towards getting real data. It also shows that the new RDE and WLTP tests, while an improvement on what was used before, are only part of the solution – those tests need to be further improved, and the imminent EU decisions on how and who approves cars for sale will be crucial to ensuring the system of approvals is independent and rigorously enforced.’
The test protocol has won one of the leading environmental prizes in Europe, the ‘Ecobest’ award. The award presented by Autobest, a federation of motoring media which gives the ‘Best car buy of the year’ award. The Autobest awards include Ecobest, a prize aimed at recognising green actions, programmes and technologies in the automotive world. The jury is made up of motoring journalists from 31 European countries.
Despite its success T&E is concerned that the European Commission is unwilling to develop a real-world emissions test as part of the new car CO2 regulation. The approach was endorsed by an independent committee but Commission officials are reluctant to take forward the work needed to implement the new test. Archer added: ‘Having undertaken independent scientific advice to look at this issue that confirmed a real-world test is the best way forward, the Commission must now act on this.’