All vehicles in the EU are subject to emissions testing prior to being released for sale in the market. Currently, this is done through a lab test called the New European Driving Cycle (NEDC), however, this is being replaced by the Worldwide Harmonised Light-Duty Vehicles Test Procedure (WLTP). WLTP will also be supplemented by the Real Driving Emissions (RDE) test that measures pollutants directly on the road. The new test will ensure that lab measurements better reflect the on-road performance of the vehicle.
There will be a phased transition between WLTP and NEDC between September 2017 and 2020. During this time vehicles will have a derived NEDC CO2 value and consumption value, as well as the WLTP CO2 and consumption values in relation to type approval. WLTP testing legislation came into effect on 01 September. Further details can be found in the timeline section.
Like NEDC (New European Driving Cycle), WLTP is a laboratory based testing procedure. There are some key differences with WLTP to provide consumption and emissions values that better reflect real world performance. The advantage of laboratory tests is that they are carried out in controlled conditions. This enables customers to gain a true comparative view between vehicle models.
Average: 34 km/h
Maximum: 120 km/h
Average: 46.6 km/h
Maximum: 131 km/h
Cold engine start
(tested at 23° C corrected for 14° C)
Cold engine start
As Volkswagen Commercial Vehicles progresses with the WLTP transition, the following type approval timings will apply:
Passenger vehicles (M type and Category N1 (i)):
Light Commercial Vehicles (Categories N1 (ii), N1 (iii) and N2):
NEDC will continue to be used for the official emissions (CO2) and fuel consumption (MPG) values. As and when WLTP figures become available for new model introductions, these will also be available for customers. It is worth noting that the NEDC CO2 values will be used for taxation purposes during the 2017/2018 tax-year, and will continue to be until further notice from the HMRC.
Although WLTP will deliver real improvements to the testing regime, it is still a laboratory test and cannot take into account driver style, traffic conditions, weather, gradients or load of the car into its calculation. All of these factors have an impact on the consumption and emissions performance of the vehicle. The RDE test will support in providing customers with this insight.
The RDE test is carried out by fitting Portable Emissions Measuring (PEMS) equipment to the car to record exhaust emissions. The test follows a standardised set of parameters, including:
The results of the RDE test will be used to validate the emissions and consumption values identified as part of the WLTP testing process.
Since 1992, the European Union (EU) has imposed strict limits on the emissions of vehicles. These are referenced as ‘Euro’ standards. Euro 6 is the latest iteration of these standards. A breakdown of the different ‘Euro’ standards levels can be found below.
New type approvals
All new registrations
Diesel particulate matter (PM)
WLTP stands for the Worldwide Harmonised Light Vehicles Test Procedure. It is a replacement for the New European Driving Cycle (NEDC) test. The test covers emissions and consumption values for vehicles.
Both test cycles are carried out in lab conditions. The WLTP test cycle has been redefined in such a way that EU Regulatory bodies view it as more representative of customer driving (ie higher speeds and loads, more dynamic accelerations, fewer and shorter stop phases). The current NEDC test measures curb weight and rolling resistance. WLTP includes the effect of options on the vehicle’s aerodynamics, rolling resistance and mass when measuring its fuel consumption and emissions.
WLTP will measure a vehicle’s individual CO2 emissions, fuel consumption (MPG) and pollutant emissions (for example NOx). This is the case currently under NEDC, however WLTP will take into account vehicle mass (including optional equipment), tyre rolling resistance class and aerodynamics. The values obtained through WLTP will be comparable worldwide.
WLTP will provide customers with greater clarity in relation to the emissions and consumption values of their vehicle. It is important to note that due to the testing aligning closer to real world emissions, this could result in higher consumption and emissions values for vehicles with combustion engines and a shorter electric range for electric vehicles (including plug-in hybrids).
Lab tests enable consumers to compare CO2 emissions and fuel consumption across different manufacturers and models in a controlled environment. As a standardised and repeatable procedure, it allows for comparison across brand and model in similar, standardised conditions.
The current lab test, known as the New European Driving Cycle (NEDC), measures fuel consumption (MPG), CO2 and pollutant emissions against EU regulations, in certain, standardised conditions. The standardised testing procedure allows the comparison of emissions between different vehicle models.
The NEDC test has been in place for a long time. Since it launched, the advancement of vehicle technology has progressed drastically. Vehicles today come equipped with an increasing amount of technologies, some of which that impact the fuel efficiency and emissions performance of the vehicle. These include heated seats, air conditioning, four wheel drive, rear window heaters to name a few.
We are underway with testing vehicles under the WLTP testing procedure for new to market vehicles. Once a vehicle has been tested under WLTP and the type approval has been issued, customers will be informed of the WLTP values for that vehicle.
NEDC CO2 values will be used for taxation purposes during the 2017/2018 tax-year, and will continue to be until further notice from the HMRC. We will update customers as further information is shared by HMRC.
WLTP is a new lab-based test cycle. It is much more representative of on-road driving, with a wider range of temperatures and speeds.
When fuels such as petrol and diesel are burned in the engine, carbon dioxide (CO2) is produced and released into the atmosphere. Levels of CO2 emissions are controlled under the ‘Euro’ standards classifications.
A diesel particulate filter is fitted to the exhaust of all Euro 5 and Euro 6 cars. It traps particulates before they leave the tailpipe.
EGR is a critical technology used to reduce the levels of NOx emitted by the engine. It involves recirculating exhaust gas back into the engine combustion chamber. This reduces the amount of oxygen, and lowers combustion temperature. Less oxygen and a lower combustion temperature reduces the amount of NOx formed.
Euro 6 is the sixth air quality emissions standard for new vehicles sold in Europe. The European Commission has enforced Euro standards since 1993. Each successive standard has been tougher in its requirements, ensuring that every new generation of vehicle uses the latest, cleanest engine and exhaust technology available.
A lean NOx trap or catalyst is an exhaust after-treatment technology, which reduces the emissions of NOx from the tailpipe (see below). It captures NOx and neutralises it in the exhaust system.
NOx refers to nitrogen oxides or oxides of nitrogen that form when fuels are burned at high temperatures, as in the engine combustion process.
Particulate matter, commonly known as soot, is a waste material of combustion.
PEMS, or portable emissions measurement system, is a sophisticated mobile laboratory in a box, which is fitted to the car and analyses tailpipe emissions while the vehicle is driven on the road or a test track.
Real world refers to conditions that affect a vehicle’s performance when it is being driven on the road, as opposed to being tested in a lab. Real world conditions are infinitely variable, making reliable and repeatable testing of emissions extremely difficult.
RDE stands for Real Driving Emissions and refers to the emissions that a car produces on the road while following a set procedure, rather than in a laboratory environment. On-road emissions can be affected by many different factors, including car and traffic conditions, temperature, weather, road surface and gradient, vehicle load and driving style.
Selective catalytic reduction (SCR) is a highly effective emissions reducing technology used in modern diesel vehicles. This specialist catalytic converter injects a urea based additive, or diesel exhaust fluid that’s often called AdBlue, into the exhaust to convert NOx into harmless nitrogen and water.
Type Approval is the official EU process new cars must pass before they can be certified for sale. It applies to many systems - emissions and safety. Cars must pass the relevant regulated tests before they are allowed to be put on the market. The VCA is the government-appointed Type Approval authority in the UK.