Article By Hartwell Editorial Team
Car exhaust

GUIDE: What Are WLTP And RDE Vehicle Emissions Standards?​

From 1st September, every new vehicle will be subjected to a much tougher emissions test, called WLTP. As a result, a car’s quoted MPG and CO2 figures are set to be a lot lower, but these figures should be far more achievable in real-world driving scenarios. Read on to find out more.

What Is WLTP?

WLTP, or Worldwide Harmonised Light Vehicle Test Procedure (should that be WHLVTP?), comes into force tomorrow, completely shaking up the economy and efficiency benchmarks we're used to. The new WLTP cycle replaces the notoriously inaccurate and outdated NEDC cycle. Both are taken in a laboratory, but NEDC produced far more favourable figures for manufacturers. 

WLTP emissions tests are far more thorough and stringent, which is why the figures will be lower for many cars. NEDC tests produced completely unrealistic MPG and CO2 that no one could replicate in real life. Vehicles were driven at a set speed for a long period of time without having to stop and start. Any acceleration and braking happened at a snail’s pace, which is unfeasible and unsafe on the road. Many companies made the most of this lax approach by setting cars up to know when they were being tested, being able to 'cheat' the system and produce outstanding figures.

Ford Edge ST-Line rear
Ford Mustang EcoBoost exhausts

When Is The Change Happening?

This change comes into effect on 1st September 2018, as dangerously high vehicle emissions levels are now becoming commonplace. WLTP is more accurate to real situations due to a more varied test cycle. A major new part of the test features a real driving emissions (RDE) segment, which is taken on real roads. It’s likely that there will still be a difference in the two figures, but by 2021 the margin will be much tighter.

Renault Megane RS exhaust

Will Car Tax Increase With WLTP And RDE?

Car tax could increase with the full introduction of these new emissions tests. Some manufacturers have reported that their CO2 figures are up to 15% higher under WLTP compared to NEDC cycles, so the same car could cost you a bit extra in tax come September.

However, many companies have already confirmed that their new car range is compliant with this new test schedule, so the figures you see are quite achievable.

If you're confused about any aspect of new car buying, tweet us @Hartwell_co_uk and we'll guide you through it!


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