WLTP is a new global standard for determining the fuel consumption and engine emissions of cars.
What Is A WLTP fuel consumption figure?
WLTP is short for 'World Harmonised Light-Duty Vehicles Test Procedure'. The WLTP replaces the NEDC test procedures introduced in 1990.
WLTP applies to all cars sold as new in the UK and is intended to present a more realistic representation of fuel consumption and engine emissions such as CO2, with a vehicle operating at low, medium, high and extra high speeds.
What Does WLTP measure?
Like the NEDC tests, the WLTP measures fuel/battery consumption and emissions from cars in laboratory simulations over different driving conditions to reflect urban driving, driving outside towns and in rural and highway conditions. The tests include acceleration, braking, pausing and resuming travel.
The tests are divided into Classes 1, 2 and 3. Each class has variations in speed, acceleration, deceleration and pauses, plus modifications to the cycles depending on the maximum speed of the car.
WLTP testing also incorporates checks on vehicle emissions of pollutants such as carbon dioxide (CO2) and oxides of Nitrogen (e.g. NOx).
These tests are undertaken in real driving using special monitoring equipment fitted to the vehicle and are known as 'Real Driving Emissions' tests.
The current protocol is 'RDE2'.
The test also include refinements to take account of vehicle payload, driving conditions, altitude and even the impact of the test equipment itself, and tests the vehicle at its lightest and heaviest weights (e.g. with and without optional features that would affect emissions, such as different transmissions and options such as air conditioning).
Company Car Taxation and Vehicle Excise Duty
From 1 April 2020 the UK has used the WLTP test results for CO2 output to determine the tax disc or vehicle excise duty for new cars (along with battery range where relevant) for the annual company car benefit.
More information about the WLTP can be found at the website of the UK Vehicle Certification Agency.