From laboratory to road: A 2014 update
Europe’s passenger-car efficiency regulation has very effectively driven down the official average CO2 emissions and fuel consumption of new passenger cars in the EU. The 2015 target of 130 grams of CO2 per kilometer (g/km) was met two years ahead of schedule and manufacturers are making good progress towards the 2020/21 target of 95 g/km.
But beneath this apparent success there is cause for concern. The basis for the regulation are results obtained under laboratory conditions using the New European Driving Cycle (NEDC)—the so-called certification or “type-approval” values. To make real progress, however, the results recorded in the laboratory must translate dependably into CO2 reductions and fuel-consumption savings experienced on the road.
This study, which builds on and extends an analysis begun in 2012 and continued in 2013, demonstrates that the year-over-year improvements reported via the type-approval tests are not reliably matched in everyday driving—and that the gap between fuel consumption measured under laboratory settings and real-world road conditions is getting wider.
The study analyzes eight different data sets covering as many as 13 model years, including both private and company cars, from Germany, the UK, the Netherlands, and Switzerland—fuel consumption and CO2 emission data from more than half a million vehicles in total. It finds that the average discrepancy between type-approval and on-road CO2 emissions increased from around 8 percent in 2001 to about 38 percent in 2013. The increase in recent years was especially steep.
For an average consumer, the discrepancy translates into increased fuel costs on the order of €450 per year. Since most EU member states base their vehicle taxation schemes at least partly on type-approval CO2 emissions, it implies significant loss of tax revenues. And it more than halves the reductions in CO2 emissions from passenger cars officially achieved by the EU over the past ten years.
The study underscores the importance of implementing the new Worldwide Harmonized Light Vehicles Test Procedure (WLTP), a more appropriate test that will produce more realistic type-approval values. The WLTP was adopted in March 2014, and the European Commission is currently preparing its implementation for the type-approval of new cars in the European Union from 2017 on. At the same time, the study highlights the need to complement the WLTP with additional measures—most importantly, some form of in-service conformity testing, to ensure that reasonable emission values are achieved not for a single test vehicle alone but for any car sold to a consumer and driven on the road.