Bay Area Rapid Transit (BART)

Bay Area Rapid Transit (BART) is a rapid transit public transportation system serving the San Francisco Bay Area in California. The heavy rail elevated and subway system connects San Jose, San Francisco and Oakland with urban and suburban areas in Alameda, Contra Costa, Santa Clara, and San Mateo counties. BART serves 50 stations along six routes on 131 miles (211 km) of rapid transit lines, including a 10-mile (16 km) spur line in eastern Contra Costa County which uses diesel multiple-unit trains and a 3.2-mile (5.1 km) automated guideway transit line to the Oakland International Airport. With an average of 411,000 weekday passengers and 118 million annual passengers in fiscal year 2019, BART is the fifth-busiest heavy rail rapid transit system in the United States and is operated by the Bay Area Rapid Transit District which formed in 1957. The initial system opened in stages from 1972 to 1974. The system was extended most recently on June 13, 2020, when Milpitas and Berryessa/North San José stations opened as part of the Silicon Valley BART extension in partnership with the Santa Clara Valley Transportation Authority (VTA)

Lines
BART operates six named and interlined heavy rail services plus one separate automated guideway line. Five of the heavy rail services run through Oakland, and all of those but the Berryessa/North San José–Richmond line and the SFO–Millbrae shuttle go through the Transbay Tube to San Francisco. All six services run on weekdays until the end of the afternoon rush hour; evenings (after about 7:00 pm), nights (after about 9:00 pm), and Sundays have as few as three services operating. Three of the services change terminals at certain times so that all stations are served during all service hours

Unlike most other rapid transit and rail systems around the world, BART lines are not primarily referred to by shorthand designations or their color names (although the colors used on maps have been constant since 1980). The services are mainly identified on maps, schedules, and station signage by the names of their termini. However, the new fleet displays line colors more prominently, and BART has begun to use color names in press releases and GTFS data