The WLTP laboratory test is used to measure fuel consumption and CO2 emissions from passenger cars, as well as their pollutant emissions. But what is the purpose of these measurements?

What is the purpose of the WLTP lab test?

Enabling comparison

The main purpose of the laboratory test is to enable the consumer to make reliable comparisons between cars in terms of their CO2 emissions and fuel economy. All conditions for vehicle set-up, testing and the handling of test results for cars are standardised and defined by EU law. This is important as it establishes a regulation that all car manufacturers and other players must follow. Only a lab test, which follows a standardised and repeatable procedure, allows consumers to compare different car models.

The same car suddenly has two different CO2 values, why is this?

Consumer information – Policy recommendations

Official documentation

Laboratory tests also play a key role in the procedure of bringing a car onto the EU market. Before cars can be put on the market, they are tested using the laboratory test cycle by a national technical service in accordance with EU legislation. When all relevant requirements are met, the national authority delivers an EU vehicle type approval certificate to the manufacturer, authorising the sale of the car type in the EU. Today, every car produced is accompanied by a certificate of conformity, which includes CO2 values based on the laboratory test. On the basis of this official document, which could be described as the car’s birth certificate, the vehicle can be registered anywhere in Europe. In some countries, the car’s certificate of conformity stays with the car/owner, in others the certificate goes to the registration authority.

The NEDC value of a car suddenly increased, what happened?

Labels and consumer information

To help drivers make a well-informed purchase decision based on fuel consumption, the Car Labelling Directive requires car dealers and manufacturers to provide relevant information to consumers. This includes a label showing a car’s CO2 emissions and fuel consumption which is attached on or near all new cars at the point of sale. The design of these labels is defined at national level, but they all contain the CO2 values or fuel consumption from the lab test that are on the car’s official certificate of conformity.

Consumer information – Policy recommendations

CO2 targets

The lab measurements are used to verify that a manufacturer’s new car fleet does not emit more CO2 on average than the targets set by the European Union. The target for average CO2 emissions of the entire EU car fleet is set at 95g CO2 per kilometre (95g/km) for 2021. Based on this, individual manufacturers have their own specific CO2 targets for their new car fleet.

Will the new WLTP test affect CO2 targets?


Most EU member states currently apply some form of CO2 tax to the registration and/or ownership of cars. These taxation systems are based on the CO2 values from the lab test, which can be found on the car’s certificate of conformity.

Will WLTP affect how much car tax I pay?

Taxation – Policy recommendations

Overview: CO2-based motor vehicle taxes in the EU in 2016

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