This is because of something called ‘WLTP’, the Worldwide Harmonised Light Vehicle Test Procedure, a brand new vehicle testing regime introduced last year to give consumers a better idea of what a vehicle’s fuel consumption and emissions will actually be. WLTP has been brought in to replace the old NEDC (New European Driving Cycle) test, which everyone knew massively overestimated the fuel economy of cars and vans.
Moving From NEDC To WLTP
The old NEDC test was designed in the 1980s, and it became increasing clear in recent years that it was outdated and needed to change, notably when it emerged that Volkswagen had been using a cheat device in its cars to adjust the engine control settings and reduced emissions when a NEDC lab test was being carried out.
The new WLTP test is designed to provide a more accurate reflection of real-world driving, with stricter test conditions, driving at higher speeds and a substantially longer test (30 minutes instead of 20) to return much more realistic pollutant, CO2 emission and fuel consumption values. In addition, WLTP also tests an individual model with its standard specification and with all the possible options, ensuring that the car is tested at its lightest and heaviest. This means tests will produce two values for each car, so the results will often be shown as a range (eg. 41.1 – 44.2mpg) or an average.
The change also means that the testing for plug-in hybrid vehicles has changed, with new tests recording fuel economy and emissions levels over longer journeys and over different test cycles - including with a flat battery - to ensure a more accurate result.
The laboratory tests will also be supplemented by a new Real Driving Emissions (RDE) test, which has been designed to measures the pollutants, such as NOx, released by cars while being driven on the road. RDE does not replace the WLTP laboratory test but complements it, helping to verify the WLTP test results from the laboratory.
Is The New Test Accurate?
No, but it’s clear that the results from the new tests are far more realistic than they were in the past. This means that higher fuel consumption figures, higher CO2 emissions and lower ranges for electric and hybrid vehicles can be expected on paper, but it will not have any detrimental effect on actual or real-world driving.
What Does WLTP Mean For Motability Drivers?
Put simply, it means that in the future your next Motability car is much more likely to match the official economy figure if it was tested under WLTP testing. It's important to remember that the new WLTP rules haven’t made cars less fuel efficient or more polluting, it’s just that the testing procedure is now longer and more thorough.
Just make sure that when you’re doing your research and comparing different Motability cars, you are comparing vehicles that have all been tested using the new regime.
Find out more at WLTP Facts, a website put together by the European Automobile Manufacturers’ Association to inform consumers about WLTP, and answer most of the common questions about the new WLTP test.