 Car sharing services have become increasingly popular in recent years, with many companies offering electric vehicles as part of their fleets. These vehicles are often touted as environmentally friendly, but they may not be as clean as advertised. In fact, the production of energy to power electric vehicles can result in significant amounts of carbon dioxide emissions. Researchers have attempted to quantify these emissions, but the data is limited. This study analyzed the actual levels of CO2 emitted from both electric and gasoline-powered vehicles used in car sharing fleets. The results showed that electric vehicles were much more efficient than gasoline-powered ones, resulting in up to 65% fewer emissions per trip. Additionally, the driving style of the driver plays a major role in determining how much CO2 is released. Operators should ensure that their drivers are aware of the importance of driving efficiently and safely, especially in cold weather conditions. This article was authored by Andrei Kubic, Katarzyna Turin, Piotr Falega, and others.