Summary: High-speed ground transportation refers to transportation systems, such as the French TGV and the Japanese Shinkansen, capable of sustained speeds of at least 125 miles per hour. In addition, magnetic levitation technology is now being developed in Germany and Japan that could carry passengers safely and efficiently at speeds of more than 250 miles per hour. Progress toward increased speeds in the United States has been limited to improving existing Amtrak routes, especially in the Northeast Corridor, where Amtrak's Metroliner hits speeds of 125 miles per hour in some stretches between Washington and New York. Whether to increase spending for high-speed ground transportation is an important decision that must be made at a time when cutting the federal deficit has made discretionary dollars increasingly scarce. Yet without more federal commitment, this new technology will not advance in the United States. If Congress decides to increase the federal role, it will need to weigh the merits of continued support for incremental improvements by Amtrak versus underwriting more ambitious--and riskier--projects by forging public-private partnerships. Congress will also need to decide whether to target the resources it makes available for specific high-speed ground transportation projects. A fuller understanding of the costs and benefits of specific projects will require reliable data.