WLTP stands for Worldwide Harmonized Light-Duty Test Procedure – a long-winded way of saying a new standard to measure fuel consumption, CO2 emissions, and range in vehicles.
What is WLTP?
The Worldwide Harmonised Light-Duty Vehicles Test Procedure is the testing standard used for all vehicles to estimate emissions and fuel consumption.
Introduced in 2017, vehicles are run through real-life driving situations, taking distance driven, speed, and duration of the test into account, as well as stop times, braking actions, acceleration phases, optional accessories, and all possible engine gearbox combinations. The averages then culminate into the vehicle’s ratings.
The test is run on every model and variant, applicable anywhere in the world, and the conditions must be replicable.
Why Are the Numbers Higher?
The new driving cycle is faster, longer, and more dynamic than the NEDC test, and reports higher fuel consumption. Although this may seem like a bad thing, it’s actually showing consumers a more accurate depiction of how much fuel a vehicle consumes while driving, allowing for more informed decisions.
Why Aren’t We Using NEDC Anymore?
The New European Driving Cycle (NEDC) was the previous way of measuring fuel consumption, range, and emissions. Last updated in 1997, the test cycle for the NEDC was deemed too lenient by the industry. Testing exclusively in laboratory settings, the NEDC didn’t take into account real-life driving conditions, equipment, variants, and other realistic standards, plus it was difficult to replicate.
Is WLTP 100% Accurate?
In short, no. The WLTP doesn’t take into account a whole myriad of things like weather conditions, road gradients, and traffic conditions. Not to mention, it’d be nearly impossible to replicate every single driver’s driving style. So, the WLTP is better than the NEDC, but it’s not going to be 100% accurate for every driver.
Who Uses the WLTP & How Does it Affect Me?
The WLTP standards are mandatory for all vehicle manufacturers and you’ll find the fuel consumption rates listed on all spec sheets.
These numbers provide you an accurate measurement of emissions, fuel consumption, and range when you look into purchasing a new vehicle, which could sway your decision.
A few more acronyms:
Real Driving Emissions: RDE
RDE is the new testing procedure that takes place on the road rather than under standardised test conditions on a test rig. RDE is also used to verify emissions (NOx) measured during the WLTP testing procedure.
Portable Emissions Measurement System: PEMS
The PEMS is the tool that measures exhaust gas emissions, NOx (nitrogen oxide), particles, and other particulates during an RDE test.