The Key System (or Key Route) was a privately owned company that provided mass transit in the cities of Oakland, Berkeley, Alameda, Emeryville, Piedmont, San Leandro, Richmond, Albany and El Cerrito in the eastern San Francisco Bay Area from 1903 until 1960, when it was sold to a newly formed public agency, AC Transit.The Key System consisted of local streetcar and bus lines in the East Bay, and commuter rail and bus lines connecting the East Bay to San Francisco by a ferry pier on San Francisco Bay, later via the lower deck of the Bay Bridge.