The study considers key factors such as ridership and safety, and includes the greater metropolitan areas of the cities. The data comes from the Federal Transit Administration and the American Public Transit Association.
Danielle Kurtzleben writes:
"All of these cities' systems have unique features that set them apart. Portland's public transit provides riders with a variety of travel options, including buses, light rail, commuter rail, streetcars, and an aerial tram. New York is unique simply by virtue of high ridership: in 2008, 4.2 billion trips were taken on New York metro area subway lines, buses, and railroads, six times the number of trips taken in Los Angeles, the No.  city. Minneapolis and Portland both feature fare-free transit routes in their downtown areas. And the Salt Lake City area's Utah Transit Authority runs ski transit lines in the winter, in addition to its usual rail and bus services, and also features wireless Internet on its buses."