The research aims to find an effective way to reduce real-world CO2 emissions of passenger vehicles, by answering the question of what kind of vehicles in various countries generates the smallest carbon footprint. Emissions were calculated for vehicles from three of the most popular segments: small, compact and midsize, both with conventional body and SUVs. Each type of vehicle was analyzed with various types of powertrain: petrol ICE (internal combustion engine), diesel ICE, LPG ICE, petrol hybrid, LPG hybrid and BEV (battery electric vehicle) with four different carbon intensity of electric energy source. The final conclusion provides guidelines for environmentally responsible decision-making in terms of passenger vehicle choice.