Particulate and carbon emissions measured on the road.

Real Driving Emissions (RDE).

The new pollutant emissions certification process also involves road testing in real driving conditions: in the latest Euro 6c, Euro 6d-TEMP and Euro 6d emissions standards, the WLTP certification in the laboratory is enhanced by a measurement of the pollutant emissions on the road. The determination of the "Real Driving Emissions", RDE for short, is to ensure that the emissions limit values for nitrogen oxides and the particle count are not just upheld in laboratory conditions, but in real road traffic. For this, PEMS devices (Portable Emission Measurement System) are attached to the vehicle and using it the proportion of pollutants in the exhaust gas during the journey is measured.

What is known as a Conformity Factor, CF, indicates the maximum amount by which the values measured in road traffic are permitted to be higher than the Euro 6 laboratory values. After a transition period, the values for nitrogen oxide and the particle count in the Euro 6d emissions standard may be up to 50% over the values prescribed in the laboratory. This markup forms the measurement tolerance of the portable measurement devices in RDE tests and should be annually checked and, if necessary, reduced.