This report summarizes key trends in fuel economy and technology usage related to model year (MY) 1975 through 2008 light-duty vehicles sold in the United States. Light-duty vehicles are those vehicles that EPA classifies as cars or light-duty trucks (sport utility vehicles or SUVs, vans, and pickup trucks with less than 8500 pounds gross vehicle weight ratings). The data in this report supersede the data in previous reports in this series. Since 1975, overall new light-duty vehicle fuel economy has moved through four phases: 1. a rapid increase from 1975 through the early 1980s, 2. a slower increase until reaching its peak in 1987, 3. a gradual decline until 2004, and 4. an increase beginning in 2005.