A new report by the International Council on Clean Transportation (ICCT) shows that the average amount of nitrogen oxides (NOx) present in exhaust emissions from modern diesel passenger cars is more than double the levels from modern trucks and buses.
The difference is attributable in large part to differences in how light-duty and heavy-duty vehicle emissions are regulated, and the contrasting performance highlights the importance of an upcoming decision on strengthening the real-driving emissions (RDE) test for passenger cars in the EU.
The ICCT paper shows data for 24 Euro 6 buses and trucks, some tested on a chassis dynamometer by the Technical Research Centre of Finland and others tested on-road using portable emissions testing equipment by the German type-approval agency KBA.
On average, NOx emissions of the heavy-duty vehicles tested were approximately 210 mg/km. Currently, NOx emissions of Euro 6 diesel passenger cars under real-world driving conditions are approximately 500 mg/km.
The European Commission plans to bring forward for discussion a package of possible revisions to the existing RDE regulation as part of a working group meeting on 17 January 17 in Brussels.
The package would include, among other changes, provisions for testing in-use, privately owned cars by independent third parties.
For more information, visit theicct.org.