It took a long time for America's average fuel efficiency to surpass the M.P.G. rating of the Model T.
The Henry Ford & Greenfield Village/AP
•1908: Henry Ford introduces the Model T. The gasoline-powered car enjoys up to 21 miles per gallon (just six m.p.g. fewer than the average new vehicle sold today).
•1935: American automakers multiply to meet a surge in demand and to capitalize on innovations made during World War I. Fuel efficiency bobs around 14 m.p.g.
•1973: Arab oil embargo creates a worldwide shortage. Fuel prices skyrocket. With US vehicles hovering around 12 m.p.g., fuel economy becomes an important selling point for new cars.
•1975: Congress enacts America's first Corporate Average Fuel Economy (CAFE) regulations, designed to improve vehicle efficiency. The Honda Civic, reaching more than 40 m.p.g. on the highway, wins top efficiency honors.
•1986: The Chevrolet Sprint achieves hybridlike efficiency with its computer-controlled carburetor, three-cylinder engine, and compact design. With 44 m.p.g. in the city and 53 on the highway, the car wins America's fuel-economy title three years in a row.
•1990: California passes legislation requiring 2 percent of new vehicles sold in the state to have no emissions by 1998.
•1991: US fuel efficiency average hits 16.9 m.p.g.