evidence: For plug-in hybrid electric vehicles, the real-world CO2 emissions were on average 3.5 times higher than the laboratory values, which confirms that these vehicles are currently not realising their potential, largely because they are not being charged and driven fully electrically as frequently as assumed. [...] For new plug-in hybrid electric vehicles (PHEVs) first registered in 2021, the real-world CO2 emissions were on average 3.5 times (4 l/100km or 100 g CO2/km) higher than the type-approval values, which confirms that these vehicles are currently not realising their potential, largely because they are not being charged and driven fully electrically as frequently as assumed. The Commission has already introduced changes to the calculation of the utility factor – the expected share of distance driven electrically – which is used to determine the CO2 emissions during the official test procedure. These changes will apply as of 2025 and may need to be further adjusted based on real-world data.