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What is the Worldwide Harmonised Light Vehicle Test Procedure (WLTP)?

The Worldwide Harmonised Light Vehicle Test Procedure is now in-force in Europe but what is it? Here’s everything you need to know about it.

What is the WLTP?

This is a new laboratory test, introduced under EU law, to measure fuel consumption and emissions of all new vehicles built and sold in Europe. It replaces the old lab test that was criticised for being non-reflective of real-world conditions. This old methodology which is still used in Australia was called the New European Driving Cycle and was introduced in the 1980s and based on theoretical driving.

The WLTP is designed around lab testing still but the intention is that the test should be more reflective of real-world driving. Thus, it covers things like low, medium, high and extra high speed segments and this is broken into braking phases, stopped phases and acceleration phases. Each test is tweaked slightly depending on the vehicle being tested and each model is tested in its lightest and heaviest form.

What are the key changes from NEDC to WLTP?

The test used to last for just 20min, it now lasts for 30min with the ‘driving’ distance increased from 11km under NEDC to 23.25km under WLTP. The average speed is also higher under WLTP, up from 34km/h to 46.5km/h and the top speed now tested is 131km/h which is up from 120km/h. And, while the NEDC used fixed gear shift points for all vehicles, the WLTP tailors the shift points to the vehicles being tested.

Will WLTP impact fuel consumption or…?

WLTP will have the biggest impact on CO2 emissions results simply because it’s a longer and more dynamic test than the old lab methodology. Fuel consumption might increase, but the test is more about achieving a more accurate CO2 result.

When will the changes come into force?

Up until the end of 2018, NEDC scores can still be used on old stock in dealerships in Europe but after that, all new cars sold will need to display WLTP figures. Any new car released after September this year will need to display WLTP results. And from 1 January 2019, only WLTP results will be allowed to be displayed on new vehicles. In Australia, however, while car makers may provide WLTP data they’ll only be required to display ADR figures which is based on the old NEDC test.

Will we ever have real-world tests?

Yes. But these tests aren’t intended to measure fuel consumption, rather they’re intended to measure NOx emissions. Europe is the first region in the world to have introduced real-world emissions testing of new vehicles. The test is called, Real Driving Emissions (RDE) test isn’t designed to replace the WLTP, it’s designed to supplement it and that’s simply because an on-road test isn’t as repeatable as a lab-based test.

How does it work? A vehicle is fitted with a portable emissions Measuring System (PEMS) with a route mapped out the vehicle must drive; this needs to cover urban roads, rural roads, highways, up and down hills, altitude changes and then have weight added to the vehicle during the journey. The intention is the check that NOx emissions don’t exceed mandated limits in real-world scenarios…we all remember how VW managed to cheat the lab test in California while its vehicles NOx emissions exceeded limits in real-world driving.

RDE has been in-use since September last year for new cars and it will be applied to all vehicles from September next year (2019). Each year, the margin for error will be reduced meaning the test results will become more reflective of real-world driving.

What about Australia?

There is no word yet on whether Australia will follow Europe and introduce stricter emissions and fuel consumption tests. While bodies like the Business Council of Australia has called on the Government to follow Europe’s lead, the plan seems to be to stick with ADR 81/02 Fuel Consumption Labelling for Light Vehicles which is based on the 20min NEDC test which has now been outdated in Europe. However, as Europe now mandates the use of WLTP more and more car makers in Australia will begin to use this data, although legally the outdated ADR 81/02 will still need to be shown on vehicle stickers.

But it’s not all smooth sailing…

We’ve already seen brands like Volkswagen hit with WLTP dramas as car makers scramble to tweak their vehicles to meet the stricter requirements of WLTP. In short, vehicles that were compliant under NEDC testing are failing the stricter lab tests. And in Europe, there are fleet targets which mean car makers need to ensure the emissions of their entire range is below a certain level. Brands like Peugeot got the jump on WLTP and began real-world testing their vehicles long before WLTP was mandated to ensure their fleet would meet its demands.

Industry forecasts suggest the end of the internal combustion engine is nigh. Diesel too. And that’s largely because car makers are unable to produce engine and transmission combinations across their product portfolio that can bring down their fleet averages. And then there’s the question of SUVs…these are the fastest-growing vehicle type around the world, yet industry analysts warn that their inherent aerodynamic deficiencies require cleaner engine and transmission options to help them meet ever more stringent fuel consumption and emissions targets in Europe.

And industry analysts also suggest that a wholesale switch to electric might not be as easy a fix as thought and that’s because of the expected strain it would place on existing electricity provision infrastructure in that demand could outstrip supply. And then there are the very real concerns of range and price.

But, the introduction of WLTP is a good thing and Europe’s strict stance on fuel consumption and emissions is forcing car makers to develop solutions rather than simply clinging to poor testing methods and rolling out vehicles that are dirtier than they could/should be.


Isaac Bober

Isaac Bober

Isaac Bober was born in the shadow of Mount Panorama in Bathurst and, so, it was inevitable he’d fall into work as a motoring writer. He began his motoring career in 2000 reviewing commercial vehicles, before becoming editor of Caravan & Motorhome magazine. He then moved to MOTOR Magazine before going freelance and contributing to Overlander 4WD, 4×4 Australia, TopGear Australia, Men’s Health, Men’s Fitness, The Australian, CARSguide, and many more.