With average weekday ridership around 165,000 passengers in June 2024, BART is the fifth busiest rapid transit system in the United States.
As of June 2024[update], Montgomery Street has the highest ridership and Oakland International Airport has the lowest.
BART's first route between Fremont and MacArthur, the Orange Line, opened in September 1972; it was extended to Richmond in January 1973.
Service began between Concord and MacArthur on the Yellow Line in May 1973, and between Montgomery Street and Daly City in November 1973.
The original system was completed in September 1974 when the underwater Transbay Tube and West Oakland opened.
BART operates five named and interlined heavy rail services plus one separate automated guideway line.
Antioch and Pittsburg Center have low platforms for use with the diesel multiple unit (DMU) trains used on that section of the line.
Two additional infill stations–the surface-level Calaveras on the Silicon Valley extension and the elevated Doolittle on the Oakland Airport Connector–are proposed but not yet funded or scheduled.