12/05/2026
**Worldwide Harmonized Light Vehicles Test Procedure (WLTP)**
WLTP is a global laboratory testing standard used to determine the levels of pollutants, CO2 emissions, and fuel consumption of traditional, hybrid, and electric passenger cars and light commercial vehicles.
Introduced to replace the outdated New European Driving Cycle (NEDC), it was designed to provide data that more accurately reflects real-world driving conditions.
# # 1. Why was WLTP introduced?
The previous standard (NEDC) was designed in the 1970s and became increasingly obsolete as vehicle technology evolved. The NEDC often produced fuel economy figures that were impossible for drivers to achieve in reality. The WLTP aims to close this gap by implementing more rigorous testing parameters.
# # 2. Key Differences in Testing
WLTP introduces several changes to make the lab test more "dynamic":
* **Higher Speeds:** The average and maximum speeds are higher than in previous tests.
* **Diverse Driving Situations:** It includes four different parts with varying average speeds: low, medium, high, and extra-high to simulate urban, suburban, main road, and motorway driving.
* **Longer Duration:** The test cycle lasts approximately **30 minutes** (up from 20 minutes under NEDC).
* **Realistic Temperatures:** Tests are conducted at more realistic ambient temperatures.
* **Vehicle Weight & Options:** Unlike the old system, WLTP takes into account the influence of optional equipment (like larger wheels or roof racks) that add weight and affect aerodynamics.
# # 3. Impact on Electric Vehicles (EVs)
For electric vehicles, the WLTP is used to calculate the **driving range**.
* **WLTP Range vs. EPA:** Generally, WLTP range figures are more generous than the US Environmental Protection Agency (EPA) ratings but more conservative than the old NEDC ratings.
* **Measurement:** It measures how many kilowatt-hours (kWh) a car consumes per 100 kilometers and determines the maximum distance a car can travel on a single full charge.
# # 4. Complementary Test: RDE
While WLTP is a laboratory test, it is often paired with **RDE (Real Driving Emissions)**. RDE involves fitting a car with a Portable Emissions Measurement System (PEMS) and driving it on actual roads to ensure that the lab results for pollutants like nitrogen oxides (NOx) are not exceeded during everyday use.