The European Union’s 2030 climate and energy framework requires the transport, building and agriculture sectors to reduce greenhouse gas emissions to 30 percent below a 2005 baseline by 2030. This study demonstrates that meeting that goal depends on deploying a combination of new transport policy measures that include mandatory carbon dioxide (CO2) standards for both passenger vehicles and heavy trucks, improving vehicle emissions testing regulations, and accelerating the transition to electric vehicles. The analysis shows that if current policies remain unchanged, CO2 emissions from cars and trucks in the EU will likely increase by 7.6 percent from 2005 to 2030, reaching 960 million metric tons (Mt) per year in 2030. Tightening the mandatory CO2 target for new passenger cars from 95 grams per kilometer (g/km) in 2021 (as measured on the New European Driving Cycle) to 78 g/km in 2025 and 60 g/km in 2030 would prevent 95 Mt of CO2 per year in 2030. However, setting a target of 68 g/km for 2025 and 42 g/km for 2030 would further increase carbon emissions averted, to 144 Mt per year in 2030. Strengthening the vehicle emissions testing system in Europe, by introducing a not-to-exceed limit for CO2 under real-world driving conditions, would help close the gap between laboratory and real-world values, and would avoid another 25 Mt of CO2 per year by 2030.