This book examines the state of development and research progress of technologies being considered for a new generation of vehicles that could achieve up to three times the fuel economy of comparable 1994 family sedans. It addresses compression ignition direct injection engines, fuel cells, gas turbines, batteries, flywheels, ultracapacitors, and power electronics being developed by the Partnership for a New Generation of Vehicles - a cooperative research and development program between the U.S. government and the U.S. Council for Automotive Research. The book assesses the relevance of the ongoing research to PNGV’s goals and schedule and addresses several broad program issues such as government efforts to anticipate infrastructure issues, the leverage of foreign technology, and the program’s adequacy and balance.