Intro

The official CO2 emissions and fuel consumption of passenger cars and vans are determined during a standardised laboratory test following the Worldwide harmonised Light-duty vehicles Test Procedure (WLTP). The WLTP is designed to represent real-world driving conditions and produce comparable results between vehicles. 

As of 2021, new vehicles have to be equipped with on-board fuel consumption monitoring devices (OBFCM) to record the amount of fuel or electric energy used and distance driven in “real-world” conditions, i.e. when the vehicle is driven on the road.

Article 12 of Regulation (EU) 2019/631 setting CO2 emission standards for cars and vans mandates the Commission to monitor the OBFCM data in order to ensure that the official WLTP values remain representative of the real-world values. The real-world data has to be collected and reported by vehicle manufacturers and Member States as set out in Implementing Regulation (EU) 2021/392. 

The Commission uses the reported data to calculate the “real-world gap”, which is the difference between the OBFCM values and the official WLTP values. A positive gap means that, on average, the vehicles concerned consumed more fuel and emitted more CO2 when driven on the road than the official test results indicated. By looking at the time trends of the gap, the Commission assesses how the real-world representativeness of the WLTP is evolving. 

The “Data” tab contains a visual overview of the main results for the first four years of the real-world monitoring (2021-2024). They are based on the data collected by vehicle manufacturers as of 2021 and by Member States as of 2023. 

The latest dataset (“reporting year 2024”) includes the data recorded and collected by 58 manufacturers and 22 Member States in the course of 2024 and reported by them in 2025. It covers new vehicles which were first registered in the EU between 2021 and 2024 (“registration year”). 

After data cleaning and processing to remove outliers, the final real-world 2024 dataset used for the calculations includes 9 923 272 vehicles (9 033 892 cars and 889 380 vans).