The average age of the passenger car fleet in Slovenia has been steadily increasing; over the past thirty years, it has risen by almost four years — from 6.8 years in 1992 to 11.1 years in 2023. Over the past two decades, the share of cars older than 12 years has been continuously growing, by around 50% each decade. At the same time, the share of cars less than three years old has been steadily declining — by roughly 30% per decade. A similar trend can be observed among other types of motor vehicles over the last twenty years (between 2001 and 2023), although the share of older heavy goods vehicles and buses has remained relatively stable in recent years, while the share of older motorcycles has slightly decreased. Fluctuations in these trends correspond to the 2008 recession and the COVID-19 pandemic in 2019–2020. The rapid ageing of the vehicle fleet means that new technologies are being adopted more slowly in Slovenia and that the overall fleet is less environmentally friendly. Similar to Slovenia, the average age of passenger cars has also increased across European countries since 2000. As drivers in the EU are delaying the replacement of old cars and the purchase of new ones, this is reflected in the growing average age of the vehicle fleet. The same trends are observed for other vehicle categories in the EU, including light commercial vehicles, heavy goods vehicles, two-wheelers, and buses.