This 2017 update of the From Laboratory to Road series covers 1.1 million passenger cars from 14 data sources and eight European countries. The analysis shows that the gap between official and real-world CO2 values increased from 9% in 2001 to 42% in 2016. For the first time, the growth in the gap shows signs of slowing down.
Since 2001, average official CO2 emission values of new European passenger cars have decreased by 30%. The rate of decline tripled after the EU introduced CO2 emission standards in 2009.
But the official CO2 emission values are determined by laboratory tests. As previous From Laboratory to Road studies, published in 2013, 2014, 2015, and 2016, showed, the gap between real-world and official CO2 emission values increased over time and effectively cancelled out two-thirds of the on-paper efficiency improvements since 2001.
For an average consumer, the gap now translates into additional fuel expenses on the order of 400 euros per year. Because vehicle taxation schemes and incentive schemes for low-carbon cars are based on official CO2 values, the gap may also lead to significant losses of tax revenue and misallocation of public funds.
This 2017 update of From Laboratory to Road study highlights the urgent need for improved test procedures and regulatory enforcement. The EU began to phase in a new test procedure, the Worldwide Harmonized Light Vehicles Test Procedure (WLTP), in September 2017. While it is expected to reduce the gap, the WLTP has its own shortcomings and should therefore be complemented by other forms of vehicle testing: random conformity testing of production vehicles by independent bodies and on-road testing of CO2 emissions. Large-scale collection of real-world fuel consumption measurements is needed to monitor progress.