Until now, all new vehicles in the EU were tested before going on sale using the New European Driving Cycle (NEDC). However, this set of tests was introduced in the 1980s and not only have cars changed with more advanced technology, road conditions and driving habits have changed as well. This old test was based on theoretical rather than the realistic driving behaviour.
Today’s cars have options like four wheel drive and air conditioning which affect emissions and economy that were not factored into the old test. This created a gap between performance in the lab and how cars actually performed in the real world.
The new WLTP tests are a major step forward. They are designed to better simulate real-world driving with new guidelines for things like ambient temperatures, tyre pressure and road resistance. A WLTP cycle also takes 50% longer than the NEDC test (30 vs 20 minutes), doubles the testing distance and increases maximum and average test speeds.