The acronym WLTP is short for "Worldwide Harmonized Light Vehicle Test Procedure" and it represents the latest method to determine vehicles' consumption and emission values. It was introduced from 1 September 2017 to replace the previous NEDC test method that was no longer considered representative of the average journeys taken by customers. Thanks to its dynamic configuration, WLTP is significantly closer to actual driving characteristics than the previously used NEDC method.

WLTP is characterised by significantly higher accelerations and a much more dynamic driving profile. The top speed is raised to 131 km/h and the average speed increases to 47 km/h.

The driving time is extended by 10 minutes, the proportion of motorway journeys increases and times when the vehicle is at standstill are reduced. The distance driven is extended to 23 kilometres. Gearshift times are calculated in advance, specifically for each vehicle and drivetrain.

All optional extras influencing vehicle aerodynamics, rolling resistance or vehicle mass are taken into account in the assessment. The power consumption of optional extras leads to increased CO₂ values.

RDE is short for real driving emissions and represents an on-road test to verify pollutant emissions. It describes vehicles'on-road emission response in real conditions. Exhaust gas measurement for the purposes of model series authorisationsused to be performed at test stations only. Since March 2016, testing has also taken place in real world conditions to bemore representative of customers’ everyday driving experiences.

A PEMS unit (portable emissions measurement system) is used to determine nitrogen oxide (NOx) and carbon monoxideemissions (CO). At a later point particulate emissions will also be determined. In this process, there is no defined cycleand test drives as well as measurements are carried out in real, everyday traffic situations in compliance with the highwaycode. Vehicles are driven on public roads for between 90 and 120 minutes, one third each in urban environments,extra-urban environments and on motorways.

In urban environments the intended average speed is between 15 km/h and 30 km/h, on motorways between 90 km/hand a minimum of 110 km/h, but no faster than 145 km/h. The ambient temperature must be between 0 and 30° and the air conditioning system must be on. Test drives must not be carried out at altitudes above 700 metres above sea leveland they must feature a maximum of 100 metres difference in altitude.

From September 2017 Euro 6 emission limit values must be complied with during RDE cycles. Stricter RDE2 regulations became mandatory for all new diesel vehicles registered from January 2021 onwards.

Requesting RDE results

RDE results of Mercedes-Benz vehicles, determined by Mercedes-Benz as the manufacturer as well as by independent,officially certified, technical service providers, can be requested using a contact form stating the PEMS test range of thecorresponding Mercedes-Benz vehicle.

The PEMS test range number associated with the vehicle is available from the homepage of the European Automobile Manufacturers Association (ACEA).

RDE result contact form

Go to PEMS test range numbers

In contrast to NEDC, the WLTP driving cycle is ten minutes longer and requires the vehicle to be stationary for 13 percent of the test. The entire cycle covers 23.5 kilometres – more than double the NEDC. It features higher average speeds of upto 131 km/h, exposes vehicles to higher fluctuations in speed and is subject to significantly more stringent test specifications.

The introduction of WLTP creates more transparency. Customers receive a more realistic, comparative benchmark for consumption and emission figures of different vehicle models.

CO₂ and consumption values also changed as a result of different testing procedures, a technically identical vehicle producing numerically higher CO₂ and consumption values.

Customers are able to determine the CO₂ values of their vehicle model much more accurately as a result of the choice of optional extras.

The data also includes a new type of equipment-specific indication: from the model with the lowest energy requirement to the model version with the highest. Numerically, this spread stretches from "WLTP low" (minimum optional extras) to "WLTP high" (maximum optional extras).