Blog: What is WLTP and what does it mean for you?

Blog: What is WLTP and what does it mean for you?

The overview:

From September 1st 2018, all new cars will have to go through a new rigorous test called WLPT - The Worldwide Harmonised Light Vehicle Test Procedure.


This change in the law aims to provide consumers with more realistic figures for each cars fuel economy and how they really perform on the road. The test will be followed by the Real Driving Emissions test (RDE) in September 2019.

What was wrong with the old tests?

The outgoing New European Driving Cycle (NEDC) test has been in use since the 1980’s and involves the car producing an average mpg (miles per gallon) in strict lab conditions, meaning the final outcome can be unrealistic to what consumers would experience on their day-to-day travels. For example, an NEDC test could claim a car is capable of 57 mpg, whereas on the road use may only produce 40 Mpg. This is partly because extras such as air con, lights, and other electronics can be switched off during testing.

What’s new with WLTP?

The new test was introduced by the European Union and has the overall aim to better represent everyday driving. This, however, could mean that figures produced through the new tests could see new cars seem 20% less efficient than before

How are the new tests conducted?

The revised tests will still take place within the confines of a lab but will aim to factor in a wider range of data such as fuel consumption, CO2 emissions, pollutant emissions, and energy consumption of alternative powertrains, as well as measuring the range of electric vehicles.


On top of this, the new test will be based on real-driving data derived from around the world that factors in aspects such as average speeds, driving phases and the difference in acceleration and braking. For each car, different engine types, gearboxes and specification types will be tested in order to easily compare different models.

How will this affect you?

From September 2018, all new cars registered will have to be certified under the new WLTP regulation, while this doesn’t sound like much, this change will indefinitely lead to a higher official g/km CO2 figure for new cars. And considering CO2 figures are one of the main factors when calculating vehicle tax, it could be mean these will rise as well.

Is there any good news?

Since you asked, yes, yes there is. Since these new regulations do not come into effect until September, it means any cars registered before they are exempt from the new tests and are still completely road legal, of course.

Therefore you can still purchase a used car without it having to meet the new requirements, leading to a lower yearly tax cost than that of a brand new 58-plate model. See, there’s always a silver lining!

In case you’re interested, here’s a list of CarShop cars that cost as little £20 to tax each year, including a large number that is totally free! 

What does the future hold?

Well, RDE tests (coming into action in 2019 that we mentioned earlier) will not replace WLTP, but simply work alongside it to provide even clearer data for consumers. This will be achieved by measuring a cars exhaust pollutants while driving, rather than fuel economy.

The results will be gathered using a nifty Portable Emission Measuring System (PEMS). This will monitor the car's performance at a range of different speeds, conditions, vehicle payloads and road types to give a more rounded final figure.

Anything else?

Nope, you’re now a certified expert on WLTP, NEDC, RDE and any other rock-band sounding emissions tests. Well, not quite, but you should be up to speed with the latest changes and what they mean for you. So, you can impress your colleagues at work with your knowledge if the topic ever arises.

  • On: 29 August 2018
  • By: CarShop

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