Even before the BART system opened, planners projected several possible extensions. Although Marin County was left out of the original system, the 1970 Golden Gate Transportation Facilities Plan considered a tunnel under the Golden Gate or second deck on the bridge, but neither of these plans was pursued. Over twenty years would pass before the first extensions to the BART system were completed to Colma and Pittsburg/Bay Point in 1996. An extension to Dublin/Pleasanton in 1997 added a fifth line to the system for the first time in BART's history. The system was expanded to San Francisco International Airport in 2003 and to Oakland International Airport via an automated guideway transit spur line in 2014. eBART, an extension using diesel multiple units along conventional railroad infrastructure between Pittsburg and Antioch, opened on May 26, 2018. BART's most significant current extension project is the Silicon Valley BART extension. The first phase extended the Fremont line to Warm Springs/South Fremont in early 2017, and the second phase to Berryessa/North San José began service on June 13, 2020. The third phase to Santa Clara is contingent upon the allocation of funding , but is planned to be completed by 2030.