AC Transit (Alameda-Contra Costa Transit District) is an Oakland-based public transit agency serving the western portions of Alameda and Contra Costa counties in the East Bay of the San Francisco Bay Area. AC Transit also operates “Transbay” routes across San Francisco and selected areas in San Mateo and Santa Clara counties. In year 2021, AC Transit includes 128 bus lines, 5,400 bus stops, a bus fleet of over 600 buses and approximately 10% are zero emission with a goal for the entire fleet to be zero emission by year 2040.