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What is RDE?

The new Real Driving Emissions (RDE) test measures the pollutants, such as NOx, emitted by cars while driven on the road.

RDE does not replace the WLTP laboratory test, but complements it. RDE serves to confirm WLTP results in real life, thereby ensuring that cars deliver low pollutant emissions, not only in the laboratory but also on the road. Europe is the first region in the world to introduce such on-the-road testing, marking a major leap in the testing of car emissions.

Under RDE, a car is driven on public roads and exposed to a wide range of different conditions. Specific equipment installed on the vehicle collects data to verify that legislative caps for pollutants such as NOx are not exceeded. Driving conditions include:

  • Low and high altitudes
  • Year-round temperatures
  • Additional vehicle payload
  • Up- and down-hill driving
  • Urban roads (low speed)
  • Rural roads (medium speed)
  • Motorways (high speed)

Even though RDE will require manufacturers to make major investments in developing new vehicles and updating their testing facilities, the automobile industry agrees that the new RDE test is needed to confirm the results of the lab tests and to ensure that cars meet specified limits once on the roads.