Toyota unveiled the Prius hybrid back in 1997, and since then the model has been through three generational changes. When Toyota released the Prius, it quickly became known as the face of hybrid vehicles and prompted many automakers to look for ways to integrate electrification into their lineups. With competition having become fiercer in recent years, Toyota needs to keep improving the Prius to keep it in the No. 1 slot in the hybrid market. And it’s exactly what it did with the fourth-generation model.