October 7, 2019

WLTP / RDE Emissions Testing Update

The Latest on WLTP / RDE Emissions Testing

You may have heard that changes occurred to the WLTP (Worldwide Harmonised Light Vehicle Test Procedure) emissions regime on 1st September 2019. If you’re not sure what those changes are, here’s a quick guide.

The WLTP ‘Second Act’

The second step in WLTP is simply a ramping up of the standards required as part of the testing regime and for a vehicle to be certified for sale. This means that any models that passed the test before 1st September will have their results run through a new set of algorithms to ensure that they meet the more stringent criteria.

The new criteria include passing the Real Driving Emissions test (see below) and meeting strict standards for evaporative emissions from the vehicle’s fuel system.

Cars that don’t meet the new standards will no longer be allowed to be sold but, as manufacturers have known about the new standards for some time, it is not expected to cause vehicle supply issues.

green driving

What about RDE?

Real Driving Emissions (RDE) testing forms part of the overall WLTP certification. It tests cars driving on real roads (in addition to the WLTP laboratory tests) and is mainly in place to ensure that vehicles do not exceed the limit of nitrogen oxides (NOx) emissions laid out under WLTP.

Up until September 1st 2019 it was not mandatory for manufacturers to put all new cars through this ‘real world’ testing to gain WLTP certification. Now, all new models must have been RDE tested before they are allowed to go to market.

Because there is inevitably a difference between the emissions measured from a car under laboratory conditions and on the road, RDE tests are being introduced in stages. The first stage (RDE1), that has just become compulsory, permits cars to emit up to 2.1 times the upper limit of NOx as measured in the lab, while being tested on the road. Cars passing this test are labelled Euro 6d-temp.

And RDE2?

RDE2 is a stricter version of the RDE test. This reduces the amount of NOx that a car can produce during its on-road testing to 1.43 times its laboratory emissions. This does not become a compulsory standard for new cars until January 2021. Cars that meet this standard will be labelled as Euro 6d compliant. From January 2023, the allowance for a difference in NOx emissions in the lab and on the road will be removed entirely for new cars.

RDE2 is important to company car drivers because diesel cars not meeting this stricter standard incur a Benefit-in-Kind surcharge of 4% on top of the rate for their car’s CO2 band.

company car tax changes

Is there a company car tax impact?

There are no direct impacts on company car tax from the changes that came into force on 1st September, but there are tax changes from April 2020 as a result of changes in the way that company car tax is calculated.

Company car Benefit-in-Kind (BiK) rates are currently calculated using a vehicle’s WLTP measured CO2 emissions, converted back to NEDC levels using a tool known as CO2MPAS. This was designed to reduce the overall tax impact of the new assessment regime for company car drivers.

From April 2020 tax calculations will switch to using actual WLTP measured CO2 emissions. The result of this will be that many cars will fall into a higher CO2 emissions band than previously. Following a period of consultation, the Government announced reductions in BiK rates for efficient petrol and diesel cars to help to mitigate these impacts.

You can find more information about company car tax and the full BiK tables here.

company car tax information