The study compared emissions from an electric car (Tesla Model 3) and a hydrogen fuel cell car (Toyota MIRAI) using a special model called GREET. The researchers found that the fuel production process is a big factor in the emissions of both types of vehicles. They discovered a need for companies to provide clearer information about how they calculate emissions from their vehicles. This research aims to highlight the importance of understanding the environmental impact of different types of green energy vehicles to help combat global warming.