WLTP Explained

We have all seen the initials quoted after various vehicle range/fuel consumption figures but some of us might be scratching our heads a little! Who and what is WLTP and exactly what does it mean when we see these numbers quoted? Well the initials stands for Worldwide Harmonised Light Vehicles Test Procedure. This is a series of tests used to measure fuel/battery consumption and emissions from passenger cars and light commercial vehicles. The WLTP was developed by the United Nations Economic Commission for Europe (UNECE) and is intended to provide more accurate and reliable data on vehicle emissions and fuel consumption compared to the previous New European Driving Cycle (NEDC) test.

In the past some range figures quoted were a little generous or perhaps in ‘ideal world’ conditions such as a flat surface, just a driver on board and nice mild conditions. Whilst different vehicle models and variants may perform differently under the same testing conditions due to factors such as engine design, transmission type, tire specifications, and vehicle weight, the WLTP test cycle is more representative of real-world driving conditions, including higher speeds, accelerations, and decelerations. This makes the WLTP results more reflective of actual driving behaviour and helps you make more informed choices when browsing new vehicles on DoneDeal based on their environmental impact.

So what exactly does the test for cars involve? In essence, it is a series of laboratory tests and driving cycles designed to measure fuel consumption, CO2 emissions, and pollutants such as nitrogen oxides (NOx), particulate matter (PM), and hydrocarbons (HC). These key focus points highlighted below help make an informed and more accurate decision.

Testing Conditions

The tests are conducted in a controlled laboratory environment under specific conditions,

including temperature, humidity, and air pressure, to ensure consistency and

reproducibility.

Test Parameters

The test parameters include factors like vehicle weight, aerodynamics, rolling resistance,

and accessory load. These parameters are specified for each vehicle type and variant.

Driving Cycles

The WLTP includes four different driving cycles with varying speeds, accelerations,

decelerations, and stops. These cycles simulate typical driving conditions, including urban,

suburban, and highway driving. Each cycle has specific characteristics designed to

represent different driving scenarios.

Test Equipment

Vehicles are equipped with precise measurement instruments to monitor fuel consumption,

exhaust emissions, and other relevant parameters throughout the test.

Test Phases

The testing procedure consists of several phases, including cold start, urban driving, extra-

urban driving, and high-speed driving. Each phase simulates different driving conditions to

capture a comprehensive range of real-world scenarios.

Data Collection

During the test, data on fuel consumption, exhaust emissions, and other parameters are

collected continuously. This data is then used to calculate the vehicle's overall fuel

economy and emissions performance.

Analysis and Reporting

Once the testing is completed, the collected data is analysed, and the results are reported

according to standardised formats. This includes information on fuel consumption, CO2

emissions, and pollutant emissions through the different driving cycles.

As of now this is a mandatory test for all vehicles sold in Europe. Currently the WLTP are aiming to harmonise testing procedures globally, enabling better comparison of vehicle emissions and fuel consumption data across different regions. This standardisation helps regulators develop more consistent vehicle emissions standards and policies worldwide and strive to refine testing procedures to better reflect actual vehicle performance and environmental impact which is no doubt, a good thing!