For the first time in years, the discrepancy between passenger vehicle type-approval test results and in-use fuel consumption and carbon dioxide (CO2) emissions did not increase, indicating a stabilization at around 39 per cent.
The average gap between official fuel consumption figures and actual fuel use for new cars in the EU has slightly decreased, to a level of 39 per cent, according to the latest update by the International Council on Clean Transportation (ICCT) to its ongoing research into vehicle fuel consumption and CO2 emissions.
“It is the first time since we began our monitoring in 2012 that we observe a slight decrease in the gap between official and real-world values, to a level of 39 per cent” says Uwe Tietge, a researcher at ICCT Europe and lead author of the study. “Until now, the gap had increased from year to year.”
This latest update of the ICCT’s annual real-world monitor is based on a statistical analysis of data for more than 1.3 million vehicles from eight European countries. The analysis draws on data from 15 different sources: the user websites spritmonitor.de (Germany), HonestJohn.co.uk (United Kingdom) and Fiches-Auto.fr (France), the fleet management and fuel card companies Travelcard (Netherlands), LeasePlan (Germany), Allstar fuel card (United Kingdom), and Cleaner Car Contracts (Belgium and Netherlands), the car and consumer magazines AUTO BILD (Germany), auto motor sport (Germany and Sweden), the vehicle testing organization Emissions Analytics (United Kingdom), the car website km77.com (Spain), the car club TCS (Switzerland), and the survey ‘Mobilitätspanel’ (Germany).
Despite the recent slowdown, the discrepancy between official measurements of vehicle efficiency and actual performance of new cars in everyday driving has more than quadrupled since 2001—a discrepancy that translates into €400 per year in extra fuel costs for the average vehicle. As a result, less than half of the on-paper reductions in CO2 emission values since 2001 have been realized in practice.
Manufacturers measure vehicle fuel consumption in a controlled laboratory environment. Since September 2018, a new test procedure, the Worldwide Harmonized Light Vehicles Test Procedure (WLTP), has to be followed for all new vehicles. The ICCT researchers speculate that increased public attention to the real-world performance of vehicles in the aftermath of Dieselgate may have led to the observed slight decrease in the gap between sales-brochure figures and the real world. “But it may just as well be the fact that all manufacturers have met their respective CO2 targets for the year 2015 and now have only limited regulatory pressure to reduce CO2 emission values of new vehicles, until the next set of targets applies in 2020” says Dr. Peter Mock, Managing Director of ICCT Europe.
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