in the heavily congested segment of the highway between, generally, Interstate 35E and US 75. This portion of the highway travels through one of the densest regions of north Dallas, which, coupled with its primary role as a circulator for commuters, makes the freeway constantly congested at all hours of the day and night. The city of Dallas's freeways, much like the city, are generally relatively new and in good condition. TxDOT is famous for its highway system in the state and many of what could be considered "flagship freeways" lie within the city. One example is North Central Expressway or US 75, which was trenched, immaculately landscaped and heavily ornamented between downtown and Loop 12 in the 1990s. Interstate 30 west of downtown Dallas was recently brought to a level near North Central Expressway and Interstate 635, Interstate 30 east of downtown, and Interstate 35E all share similar futures. Construction, like many cities, is a constant burden for the city's heavily automobile-centered culture. Mass transportation Dallas Area Rapid Transit (DART) is the Dallas area public transportation authority, providing bus and rail service. DART began operating the first light rail system in the Southwest United States in 1996 and continues to expand its coverage. Currently, four light rail lines are in service. The goes through Oak Cliff, downtown, Uptown, North Dallas, Richardson and Plano. The goes through South Dallas, downtown, Uptown, North Dallas, Garland, and Rowlett. The goes through south east Dallas, Fair Park, Baylor University Medical Center, downtown, Victory, west of Dallas Love Field, Farmers Branch, then ends in Carrollton. The follows the Dart Red Line from North Plano through downtown, then follows the Green Line up through Victory, to Bachman Station, then goes west to Las Colinas before terminating at DFW Airport. All current rail lines are connected downtown by four rail stations. Red, Orange and Blue Lines connect to Cityplace/Uptown Station, currently the only subway station in the Southwest. DART completed expansions to the Orange line in 2014, bringing the length of the light rail system to around . Further ambitions include expanding the commuter rail network in the region to over ; expanding the DART light rail network to over with a second route through downtown included; expanding the Dallas Streetcar to the Bishop Arts District and Convention Center Hotel; and expanding the elevated Las Colinas Area Personal Transit system to serve new entertainment venues in