California is home to two heavy rail metros, which moved an average of 509,500 passengers every weekday during the third quarter of 2010.
Systems listed in order of average weekday ridership*
BART (358,500) – San Francisco Bay Area Rapid Transit District
Metro Rail Red & Purple Lines (151,000) – Los Angeles County MTA
*Figures from American Public Transportation Association’s Q3 2010 Ridership Report.