Alternative fuels and advanced vehicle technologies can reduce air pollution and protect public health, while also improving national security by reducing U.S. dependency on petroleum. Currently, transportation accounts for over two-thirds of all petroleum used in this country. While still maturing, many alternative fuels and advanced vehicle technologies are now practical. The Environmental and Energy Study Institute and the Northeast Sustainable Energy Association hosted a briefing in which panelists shared experiences with their use of hybrid technologies and compressed natural gas (CNG), biodiesel and clean diesel fuels. The panelists concluded that the remaining challenges in establishing the widespread use and availability of these technologies are not technical, but rather are economic in nature. Federal, state and local governments can play a large role in overcoming this economic barrier by encouraging wide-scale adoption of alternative fuels and advanced vehicle technologies in government fleets. This would provide the market demand necessary to jumpstart these technologies by giving manufacturers the incentive to increase investment and hasten the achievement of economies of scale.