People in the San Francisco Bay Area rely on a complex multimodal transportation infrastructure consisting of roads, bridges, highways, rail, tunnels, airports, seaports, and bike and pedestrian paths. The development, maintenance, and operation of these different modes of transportation are overseen by various agencies, including the California Department of Transportation (Caltrans), the Association of Bay Area Governments, San Francisco Municipal Transportation Agency, and the Metropolitan Transportation Commission. These and other organizations collectively manage several interstate highways and state routes, eight passenger rail networks, eight trans-bay bridges, transbay ferry service, local and transbay bus service, three international airports, and an extensive network of roads, tunnels, and bike paths.

The Bay Area, especially San Francisco, are frequently listed as one of the best and most extensive cities and/or metropolitan areas in the United States for public transportation.^[1][2] Local trips on transit are frequently accomplished by bus services. Different agencies serve different corners of the Bay Area, such as samTrans serving mostly San Mateo County and County Connection connecting the suburbs of Contra Costa County; though some bus agencies operate transbay services, such as Golden Gate Transit. While ferries also connect communities across the bay, most transbay and longer-distance trips on public transportation, however, use rail-based transit. Bay Area Rapid Transit (BART) is the sole rapid transit system within the bay and the dominant provider of regional transportation between San Francisco, northern San Mateo County, and much of the East Bay. The Bay Area is also home to various commuter rail services, such as SMART within Sonoma and Marin counties, Caltrain on the San Francisco Peninsula, ACE between San Jose and Stockton, and various Amtrak routes out of Oakland and San Jose. San Francisco is also the home of the world's last manually-operated cable car system, and both San Francisco's Muni and Santa Clara's VTA operate light rail networks to complement their bus services. With few exceptions, most public transit within the Bay Area can be paid for by using the Clipper card.

Though not as extensive as Southern California's freeways, the Bay Area is also home to an extensive network of highways. Four bridges traverse the San Francisco Bay itself, and four more traverse the northern San Pablo Bay, in addition to more localized expressways such as US 101 and Interstate 280 in the Peninsula, Interstates 680 and 880 in the East Bay, and Interstate 505 in the north. Many highways have tolled express lanes, paid for by using FasTrak. Streets within the Bay Area vary from wider stroads such as El Camino Real in the Peninsula, to denser slower streets within urban cores, to scenic routes like California State Route 1. However, San Francisco has historically approached freeways with hostility, and activists have moved to stop the construction of new highways and tear down existing ones, most notably inciting the 1991 demolition of the Embarcadero Freeway. The city today is seen as the birthplace of American highway revolts.^[3]

Airports

The Bay Area has four airports served by commercial airlines, three of which are international airports. In addition to these airports, there are many general aviation airports in the region.

• San Francisco International Airport (SFO)

  The busiest in the region and the second busiest in the state after Los Angeles International Airport. A hub for Alaska Airlines and United Airlines. For United, SFO is the primary transpacific gateway for its route network.

• San Jose International Airport (SJC)

  The second-busiest and fastest-growing airport in the Bay Area.^[4][5] It serves as a focus city for Alaska Airlines.^[6]

• San Francisco Bay Oakland International Airport (OAK)

  The third-busiest airport in the region and an operating base for Southwest Airlines.^[4] San Francisco Bay Oakland International Airport is the oldest of the Bay Area's civilian airports still in use. The site was chosen due to good weather conditions for aircraft operations.

• Charles M. Schulz–Sonoma County Airport (STS)

  The smallest of the Bay Area airports served by commercial airlines.^[7]

Airport transportation

All major Bay Area airports are located near freeways and are served by public transportation, ride-share services, and various private shuttle bus operators.

Major airport/public transportation connections

• San Francisco International Airport can be directly accessed through BART at the SFO station at the International Terminal. Using BART, riders can also transfer to Caltrain at the nearby Millbrae station. SFO also has an inter-terminal AirTrain service.
• San Jose International Airport can be accessed by VTA Route 60, which connects to BART, Caltrain, VTA light rail and other bus and rail services at the Santa Clara Transit Center, Metro/Airport station and Milpitas station. The airport also operates an inter-terminal shuttle bus.
• San Francisco Bay Oakland International Airport is connected to BART by the Oakland Airport Connector between the airport and Coliseum station.
• Sonoma County Airport is directly connected to SMART commuter rail at the Sonoma County Airport station.

Public transportation

Public transportation in the San Francisco Bay Area is quite extensive, including one rapid transit system, three commuter rail lines, two light rail systems, two ferry systems, Amtrak inter-city rail services, and four major overlapping bus agencies, in addition to dozens of smaller ones. Most agencies accept the Clipper Card, a reloadable universal electronic payment card.

An extensive rail infrastructure that provides a mix of services exists within the nine Bay Area counties. Bay Area Rapid Transit, commonly known as BART, provides rapid transit service between San Francisco and Contra Costa, Alameda, San Mateo, and Santa Clara counties. Caltrain, which runs on the right-of-way of the historic Southern Pacific Railroad, provides commuter rail service on the San Francisco Peninsula, linking the cities of San Francisco, San Jose, Gilroy, and numerous peninsula cities in between. The Millbrae Intermodal Terminal provides transfers between Caltrain and BART. The Altamont Corridor Express, commonly known as ACE, also provides commuter rail service, but from the Central Valley into Silicon Valley, terminating at San Jose's Diridon Station. To the north, Sonoma–Marin Area Rail Transit (SMART) line provides commuter rail service in Sonoma and Marin counties.

In addition, Amtrak has a presence throughout the Bay Area. There are two intercity services: the Capitol Corridor connects Bay Area cities to Sacramento, and the San Joaquins connects to cities across the San Joaquin Valley. Additionally, there are two long-distance services, the Coast Starlight offers service to Seattle and Los Angeles, while California Zephyr runs to Chicago via Denver.

The Bay Area also has two light rail systems: one run by San Francisco Municipal Railway called Muni Metro, which operates within the city of San Francisco, and the other run by the Santa Clara Valley Transportation Authority, which operates within Santa Clara County.

A series of overlapping bus agencies provide additional public transit coverage to Bay Area regions both served and not served by rail transit. The four largest agencies, Muni, AC Transit, SamTrans, and VTA operate within the City of San Francisco, East Bay, the Peninsula, and South Bay respectively, although their service areas generally overlap with neighboring agencies and numerous smaller agencies. All of these agencies also provide limited night bus service, which are intended to "shadow" the rail routes that are closed during the nighttime hours for maintenance. In addition, the four bus agencies are each independently pursuing constructing bus rapid transit systems by developing separated right-of-ways and traffic signaling on busy corridors, including on Geary and Van Ness for Muni, El Camino Real for SamTrans and VTA, and International Boulevard for AC Transit.

Although BART and certain bus agencies provide travel over (or under) the San Francisco Bay, Golden Gate Ferry and San Francisco Bay Ferry provide ferry service across the bay.

Most systems allow bicycles onto their systems with no additional charge. In addition, Bay Area residents may rent bicycles from the Bay Wheels bike share in certain parts of San Francisco, San Mateo, and Santa Clara counties.

Rapid transit

Agency		Train Example	Service Area	Daily ridership[a]	Clipper Payment Option	Routes	Stations	Track Length	Track Gauge
BART	Blue, Green, Orange, Red and Yellow Lines		San Francisco, Alameda, Contra Costa, San Mateo and Santa Clara counties	152,500	Yes	5	50	131 mi (211 km)	5 ft 6 in (1,676 mm) broad gauge
	eBART		Eastern Contra Costa County	4,100	Yes	1	3	10.1 mi (16.3 km)	4 ft 8+1⁄2 in (1,435 mm) standard gauge
	Oakland Airport Connector		Oakland International Airport	1,100	Yes	1	2	3.2 mi (5.1 km)	—

Commuter rail

Agency	Train Example	Service Area	Daily ridership[a]	Clipper Payment Option	Routes	Stations	Track Length	Track Gauge
ACE		San Joaquin, Alameda and Santa Clara counties	2,700	No	1	10	86 mi (138 km)	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Caltrain		San Francisco, San Mateo and Santa Clara counties	20,900	Yes	1	32 1 planned	77.4 mi (124.6 km)
SMART		Marin and Sonoma counties	2,600	Yes	1	12 4 planned	45 mi (72 km)

Long-distance and intercity rail

Agency		Train Example	Service Area	Daily ridership[9]	Clipper Payment Option	Routes	Stations	Track Length	Track Gauge
Amtrak California	Capitol Corridor		Santa Clara, Alameda, Contra Costa, Yolo, Sacramento and Placer counties	2,500	No	1	17	168 mi (270 km)	4 ft 8+1⁄2 in (1,435 mm) standard gauge
	San Joaquins		Alameda and Contra Costa counties in the Bay Area section of its route	2,300		1 to Bay Area (2 total)	4 in the Bay Area (16 total)	315 mi (507 km)
Amtrak	California Zephyr		Alameda and Contra Costa counties in the Bay Area section of its route	900		1	3 in the Bay Area (33 total)	2,438 mi (3,924 km)
	Coast Starlight		Alameda, Contra Costa and Santa Clara counties in the Bay Area section of its route	930		1	3 in the Bay Area (28 total)	1,377 mi (2,216 km)

Light rail

Agency		Train Example	Service Area	Daily ridership[a]	Clipper Payment Option	Routes	Stations	Track Length	Track Gauge
Muni	Muni Metro		San Francisco	75,500	Yes	6	33 (+ 87 additional stops)	34.6 mi (55.7 km)	4 ft 8+1⁄2 in (1,435 mm) standard gauge
	Heritage streetcars (E Embarcadero1, F Market & Wharves)					2	36	6 mi (9.7 km)
	Cable cars			14,900 (2019)[10]		3	52 stops	5.1 mi (8.2 km)	3 ft 6 in (1,067 mm)
VTA light rail			Santa Clara County	14,400		3	62	42.2 mi (67.9 km)	4 ft 8+1⁄2 in (1,435 mm) standard gauge

¹The E Embarcadero was suspended due to the COVID-19 Pandemic and as of March 2024 has yet to resume.^[11]

Bus services and stations

The Transbay Terminal serves as the terminus for Greyhound long-distance bus services and as a hub for regional bus systems AC Transit (Alameda & Contra Costa counties), WestCAT, SamTrans (San Mateo County), and Golden Gate Transit (Marin and Sonoma Counties).^[12]

There are several bus stations in the San Francisco Bay Area including Fairfield Transportation Center, Richmond Parkway Transit Center, Naglee Park and Ride, Hercules Transit Center, Curtola Park & Ride, Eastmont Transit Center, San Rafael Transit Center and many bus bays at BART stations.

Major bus agencies

Agency Name	Bus Example	Service Area	Daily ridership[a]	Clipper Payment Option	Number of Routes
					Local	Rapid/ Limited	Express/ Commuter	Shuttle	All-Nighter
AC Transit		Entire: Inner East Bay (western Alameda County and western Contra Costa County) Parts of: San Francisco, San Mateo and Santa Clara counties	164,100	Yes	68	4	29	—	6
SamTrans		Entire: San Mateo County Parts of: San Francisco and Santa Clara counties	32,400		30	—	1	—	2
Muni		Entire: San Francisco Parts of: Marin and San Mateo counties	309,200		42	5	16	—	10
VTA		Entire: Santa Clara County Parts of: San Mateo County	71,600		54	5	12	12	1
Note: Some routes that operate as one route type may also be listed as another type (e.g. select daytime AC Transit, Muni, and VTA services also operate as All-Nighter routes)

Minor bus agencies