WLTP and RDE – the new test process.
Certification processes are also getting long in the tooth. That's why the "Worldwide Harmonized Light Vehicles Test Procedure", WLTP for short, is replacing the NEDC process for determining the consumption and emission values. The "New European Driving Cycle" (NEDC) was initially developed as a theoretical measurement run and has been in application Europe-wide since 1992. However, a modern certification process is expected to deliver values that are as realistic as possible. The NEDC process no longer meets this requirement. That's why the new WLTP process was developed by an initiative of the United Nations Economic Commission for Europe (UNECE). The new WLTP cycle is based on empirically collected, real driving data from routes in Asia, Europe and the USA and is thus significantly more representative.
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.
More transparent and closer to the consumption on the road.
The WLTP process reduces the difference between the values determined on the test rig and the real consumption values. This is down to the new driving cycle, which better illustrates today's driver profiles. Furthermore, the consumption values have to be specifically identified for each vehicle. In other words: in the determination of the certification values, the mass, the air and rolling resistance as well as the optional extras are taken into account. Add to this the determination of the "Real Driving Emissions", RDE for short, which ensures that the emissions limit values for nitrogen oxides and the particle count are not just upheld in laboratory conditions, but in real road traffic.
Nevertheless, WLTP cannot deliver "individual" consumption values. It remains a standardised test cycle, which cannot illustrate the personal consumption of each driver. The actual consumption of a vehicle on the road is largely dependent on the individual driving style, on route profile, on traffic, on the load of the vehicle and on external conditions, such as temperatures. This cannot be entirely reproduced with a standardised test process.
WLTP & RDE at a glance
| Fewer pollutant emissions for better air quality. |
Different dates of application EU-wide. |
| Determining fuel consumption and emissions more realistically: the new WLTP process. |
Uniform certification, different taxation. |
| Particulate and carbon emissions measured on the road: Real Driving Emissions (RDE). |
Drive intelligently, save fuel. Efficiency optimisations through driving style. |