Toyota

The Toyota Prius continues to lead the market for hybrid automobiles that it started over a decade ago. With its 50-MPG fuel economy rating, Prius is the most fuel-efficient passenger car available in the U.S. today. The Toyota Prius - now synonymous with "hybrid" - entered the market in 1997 as the world's first mass-produced hybrid. The company's exclusive Hybrid Synergy Drive System was introduced in 2004 on the second-generation Prius. The Prius helped boost public awareness for the automobile's role in the environment, specifically putting a focus on improving fuel efficiency and reducing carbon emissions.