High Quality Content by WIKIPEDIA articles! The Greater Miami area, comprising the three counties of Miami-Dade, Broward, and Palm Beach, known collectively as South Florida, is home to a wide variety of public and private transportation systems, including heavy rail mass transit (Metrorail), commuter rail (Tri-Rail), light rail (Metromover), highways, two major airports (Miami International (MIA) and Fort Lauderdale-Hollywood International (FLL)) and seaports (Port of Miami and Port Everglades), as well as three county-wide bus networks (Metrobus (Miami-Dade), Broward County Transit (BCT), and Palm Tran), which cover the entire urbanized area of South Florida. Census and ridership data show that Miami has the highest public transportation usage of any city in Florida, as about 17% of Miamians use public transportation on a regular basis, as well as about 4% of those in the South Florida metropolitan area. The majority of public transportation in Miami is operated by Miami-Dade Transit (MDT). Miami-Dade Transit is the largest transit system in Florida and the 12th largest transit system in the United States.