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What is WLTP and should you care?

Have ever asked yourself, what is WLTP? If the answer was no, this is the wrong article for you because we are about to explain everything there is worth knowing about the new emissions and fuel economy test in Europe.

Baton down the hatches, glue down your ornaments and hold on tight for Recombu Cars is about to explain what on earth the WLTP acronym is all about and why you may want to care. We can tell you are incredibly excited.

By the end, we can only hope you are fully enlightened to the point you positively glow with knowledge. If not, feel free to ask any questions in the comment below and we will do our best to answer them. Now to business.

What is WLTP?

WLTP is short for the Worldwide Harmonised Light Vehicle Testing Procedure, which is the new EU test for vehicle emissions and fuel economy.

It was quietly launched in September, 2017, in the wake of the VW emissions scandal but had actually been in the works since 2007. It is increasingly being used by car manufacturers and that trend is going to continue for reasons we will get to in a second.

So what does the WLTP test involve?

Though the testing of carbon dioxide (CO2), nitrogen oxide (NOX) and carbon monoxide (CO) remains the same, as well as looking at particulate mass (PM) and particulate number (PN), the way the test is conducted is more thorough than the old New European Driving Cycle, which came into play back in the 1980s.

WLTP incorporates three test cycles. There are also four test phases: Low, medium, high and extra high speed. These are designed to cover A-road, city, motorway and urban driving scenarios.

Not only that, the environmental impact of certain optional extras will be factored in such as air conditioning and other drains on the engine and battery, with each powertrain configuration tested at its lightest (most economical) and heaviest (least economical).

To be specific, the WLTP test incorporates a 30-minute drive over 14.4 miles. During that time the vehicle will average 28.9mph and hit up to 81.3mph, with gear changes made along the way. Temperatures range from 14 and 23 degrees Celsius.

These changes make it harder for manufacturers to cheat the system, especially when the second part of the test actually happens on a road and not inside a laboratory. Known as the Real Driving Emissions (RDE) test, cars will be driven while a machine (known as the Portable Emissions Measurement System or PEMS for short) breathes in exhaust fumes and works out the level of pollution.

An update to emissions and fuel economy testing was long overdue, particularly in light of numerous manufacturers boasting figures that were usually inaccurate – wildly so on occasion. This is why it is thought that most (but not all) cars that take the new test will see figures worsen by around 20 per cent.

What are the benefits of WLTP, then?

With real-world pollution limits to adhere to, WLTP should encourage cleaner, more efficient vehicles on European roads. That is the plan anyway – loopholes can and almost certainly will be found and exploited in some way. At the very least, then, the figures quoted in adverts will be closer to real life but how close is hard to say right now.

Obviously second-hand cars are exempt from being tested, but other measures such as a tougher MOT in the UK and emissions charges such as the London Congestion Zone will encourage owners of less economical and more polluting vehicles to consider something more efficient.

WLTP vs NEDC: What’s the difference?

For comparison’s sake, the NEDC test involves a 20-minute drive across 6.8 miles (nearly half of the WLTP distance) at speeds between 21mph and 75mph. Gear shift points are fixed, as opposed to vehicle-dependent, and the temperature range is 20 to 30 degrees Celsius. It is comprised two test phases and a single test cycle.

You forgot to mention EPA

Well remembered. EPA stands for ‘Environmental Protection Agency’ and is the name for a federal agency that measures fuel economy ratings for vehicles in the US. It has nothing to do with ‘IPA’, which stands for India Pale Ale and is a rather delicious type of beer.

Like NEDC, the tests are taken in a lab under conditions that can allow for higher figures than what you would see in actual driving conditions. It is, however, usually more accurate than NEDC (especially for electric car ranges) but applies to vehicles sold in North America.

Considering the US opted out of WLTP early and it could stay that way, EPA is here to stay. At least EPA is much closer to WLTP than NEDC in terms of accuracy.

Will the WLTP test be used for electric vehicles?

It will, indeed, as well as for hybrids and plug-in hybrids. Basically if you can drive it on the road and it is a new vehicle, it will be subjected to the WLTP test (minus the odd bizarre exception). Given that electric and plug-in hybrids can travel without using an engine, local emissions will obviously be zero.

What will change with regard to electric vehicles is that a longer test will see the manufacturer driving range claims drop. An example is the 2018 Nissan Leaf, which is quoted at 168 miles WLTP where it scored 235 miles NEDC and 151 miles EPA.

So when will all figures be quoted as WLTP?

The introduction of WLTP is being done in two stages. The laboratory element is mandatory for all new European vehicles being homologated now and all vehicles on sale will have been conducted by the 1st of September, 2018.

Second up is the RDE element, which will need to have been completed by the 1st of September, 2019. You should see all manufacturers using WLTP by 2021, signalling the end of NEDC.

Any negatives of WLTP?

A robotic machine will drive more efficiently than you ever could and that is therefore the weakest link in the WLTP test. Motorists with a heavy foot will, for example, eat the range of their electric car far more quickly, especially if it is cold outside, the headlights are on and their favourite Enya album is blaring.

From the perspective of car manufacturers, testing the permutations of alloy wheel sizes and various gadgets and gizmos such as navigation and air conditioning will prove more timely and therefore more expensive, which could have a knock-on effect in some form.

Car-specific revisions designed to help cars pass the test, such as a continued focus on small displacements and big turbos, will also continue to happen. Vehicles with higher outputs, meanwhile, may end up jumping up a bracket or two in terms of road tax in the UK, making them less attractive to consumer and business buyers.

The focus on electrification will also continue its march onward, with many manufacturers already making significant process in that respect or having at least made some sort of announcement to that effect. Jaguar Land Rover (JLR), for instance, says it will offer an electrified version of every car it offers by 2020. Volvo is aiming for the same goal by 2019.

Will WLTP apply to emissions targets arriving in 2021?

Yes, but the answer is a little more complicated. NEDC figures will still be used as a basis for what emissions requirements manufacturers have to meet, but those figures will be derived from WLTP figures translated back into NEDC. So panic not, your lungs should be subjected to cleaner and cleaner air going forward.

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