Distrito de Transporte Rápido del Área de la Bahía
When the SFO/Millbrae extension opened on June 22, 2003, BART extended the Dublin/Pleasanton–Daly City line to SFO. BART truncated this line back to Daly City and rerouted the Pittsburg/Bay Point line to SFO in its place on February 9, 2004. San Mateo County is not a member of the San Francisco Bay Area Rapid Transit District, so SamTrans funded the county's BART service. When the extension's lower-than-expected ridership caused SamTrans to accrue deficits, BART agreed to SamTrans' request to operate only this line south of Daly City effective September 12, 2005.