Portland, Ore., a city known for its innovations in public transportation, is home to the nation's second commuter aerial tramway. At 22 miles per hour, the award-winning Portland Aerial Tram transports people 3,300 feet through the air in a matter of three minutes. In the first few months of this year, the tram will have made its 250,000th trip since opening in January 2007. For more on the city's transportation, read Governing's March feature, "Portland Struggles to Remain a Leader in Public Transit."