Passenger rail systems provided 10.7 billion passenger trips in the United States in 2008.11 The nation's passenger rail systems include all services designed to transport customers on local and regional routes, such as heavy rail, commuter rail, and light rail services. Heavy rail systems-- subway systems like New York City's transit system and Washington, D.C.'s Metro--typically operate on fixed rail lines within a metropolitan area and have the capacity for a heavy volume of traffic. Commuter rail systems typically operate on railroad tracks and provide regional service (e.g., between a central city and adjacent suburbs). Light rail systems are typically characterized by lightweight passenger rail cars that operate on track that is not separated from vehicular traffic for much of the way. All types of passenger rail systems in the United States are typically owned and operated by public sector entities, such as state and regional transportation authorities.