• Banning new internal combustion engine cars reduce tailpipe CO 2 emissions. • A ban in 2030 is not sufficient for reaching Swedish climate targets for 2030. • An earlier ban year or increased biofuel use is needed to reach targets. • Regulation of carbon footprints for new vehicles and/or batteries may be motivated. • Prospective lifecycle assessment and vehicle fleet turnover simulations are used. Banning sales of passenger cars with internal combustion engines is becoming a common climate change mitigation policy. This study analyzes the effects of such a ban on the carbon footprints of passenger car travel in Sweden using a novel vehicle turnover model and prospective lifecycle assessment, with scenarios for decarbonization of supply chains. A ban on internal combustion engines results in significantly decreased carbon footprints primarily due to reduced tailpipe CO 2 emissions. The full effect of a ban is delayed due to fleet inertia. Increasing the pace of electrification is beneficial for the carbon footprint regardless of global manufacturing decarbonization pathways. A ban in 2030 is not sufficient to reach national policy targets for the transport sector, requiring either an earlier ban (i.e., 2025) or increased biofuel use. Risks of carbon leakage may motivate extending current regulations of vehicle-specific tailpipe emissions to also cover carbon footprints for new cars.