The San Francisco Bay Area Rapid Transit District (BART) is a heavy rail public rapid-transit system serving the San Francisco Bay Area. The acronym BART is pronounced as a word, not as individual letters.

BART today
BART comprises 104 miles (167 km) of track and 43 stations. The system uses a 5 feet 6 inches (1.7 m) broad rail gauge, as opposed to the 4 feet 8.5 inches (1.4 m) standard gauge predominantly found in the United States. The broad gauge was selected to provide greater stability in part due to the planned Golden Gate Bridge route and to provide wider seats, aisles, and a smoother ride for the lightweight aluminum and fiberglass cars.
Current is delivered to the trains over a third rail, the position of which alternates relative to the context of the train. Inside stations, the third rail is always on the side furthest away from the passenger platforms. This design feature eliminates the danger of a passenger either falling directly on the third rail, or stepping onto it to climb back to the platform should they fall off. On ground-level trackways, the third rail alternates from one side of the track to the other, providing breaks in the third rail to allow for emergency evacuations across trackways.
Underground tunnels, aerial structures and the transbay tube have evacuation walkways and passageways to allow for train evacuation without exposing passengers to easy, inadvertent contact with the third rail, which is located as far away from these walkways as possible. The voltage over the third rail is 1,000 V DC; as a result, there are notices through the system warning passengers of its danger. In addition, BART posts notices inside each train car warning of the third rail and the four paddle-like rail contact shoes protruding from the underside of each car by the rail wheel trucks.
Many of the original system 1970s era BART stations especially the aerial stations feature simplistic Brutalist architecture.

System details
The BART system consists of five lines, but most of the network consists of more than one line on the same track. Trains on each line typically run every fifteen minutes on weekdays and twenty minutes during the evenings, weekends and holidays; however, since a given station might be served by as many as four lines, it could have service as frequently as every three to four minutes. As of 2006, BART service begins around 4:00 a.m. on weekdays, 6:00 a.m. on Saturdays, and 8:00 a.m. on Sundays. Service ends every day near midnight with station closings timed to the last train at station. Two of the five lines, the Richmond and Fremont lines, do not have night (after 7 p.m.) or Sunday service, but all stations remain accessible by transfer from the other lines.

Hours of operation and frequencies
Unlike most other rapid transit and rail systems around the world, BART lines are generally not referred to by shorthand designations. Although the lines have been colored consistently on BART system maps for more than a decade, they are only occasionally referred to officially by color names, and only rarely referred to in this way by members of the public (e.g., the "Red Line").
BART makes aggressive use of interlining, where multiple lines merge and share the same stations and tracks. Four lines share the Transbay Tube, all San Francisco stations, the Daly City Station and West Oakland Station. As a result, there are times of significant congestion during peak hours as multiple lines vie for shared resources. Only a maximum frequency of 4½ trains per hour per line can be achieved after headways and dwell times are accounted for. The lack of passing tracks or sidings throughout this quadruple-interlining section makes for very challenging recoveries from traffic delays. San Francisco- and Peninsula-bound trains from the East Bay must ensure that proper sequencing is maintained prior to entering the merged section for operations to remain smooth and without significant delays.

Current lines
In 1996 when the I-680/Highway 24 interchange in Walnut Creek was overhauled for construction, BART added temporary commuter train service during rush hours, which ran between South Hayward and Concord stations. The service ceased when the interchange was finished.
At the time when the BART-SFO Extension opened on June 22, 2003, there was a Millbrae - SFO Line, a shuttle line that operated every 20 minutes between Millbrae and San Francisco Airport, formerly depicted as a purple line. This line has been defunct as of February 2004. It has since been replaced by the Dublin/Pleasanton - Millbrae line that stops at SFO Station on its way to Millbrae. As of the latest service changes approved by BART's board, this service will be completely eliminated; passengers traveling from points south to the airport would have to board a train at Millbrae, travel to San Bruno, and then take a different train back to the airport.

Defunct lines
BART operates four types of cars, built from three separate orders. The A cars and the B cars were built from 1968 to 1971 by Rohr Industries, an aerospace manufacturing company which had only recently made its foray into mass-transit equipment manufacturing, touting yet untested space-age design techniques. The A cars were designed as leading or trailing cars only, with a fiberglass operator's cab housing train control equipment and BART's two-way communication system. The A cars are distinguished by their aerodynamic leading edge extending 5 feet (1.5 m) longer than their B- and C-car siblings. The A car can comfortably seat 72 passengers, and under crush load, 150 passengers. B cars have no operator's cab and are used in the middle of trains to carry passengers only; B cars have the same passenger capacity as the A cars. Currently, BART operates 137 A cars and 303 B cars. BART's livery has remained effectively unchanged throughout its history.
The C cars were built by Alstom between 1987 and 1989. The C cars have a similar fiberglass operator's cab and control and communications equipment as the A cars, but unlike A cars, do not have the aerodynamic nose design, thus allowing them to be used as middle cars as well. The dual purpose of the C cars allows faster train-size changes without having to move the train to a switching yard. C cars can comfortably seat 64 (4 seats were lost compared to the A/B cars by eliminating one row of seats to accommodate the operator's cab and 4 additional seats were lost by eliminating one pair of seats next to the left-side forward door on each side to provide space for wheelchairs) and under crush load accommodate 150 passengers. The latest order, from Morrison-Knudsen (now Washington Group International), was for C2 cars, which are essentially the same as C cars, but feature an updated, third-generation interior with a blue/gray motif, in contrast to the previous blue and brown colors. C2 cars have flip-up seats near the left-side forward door to accommodate passengers in wheelchairs, and red lights on posts near the door to warn the hearing-impaired when the doors are about to close. C2 cars can comfortably seat 68 passengers (including the flip-up seats), and under crush load can carry 150 passengers. Since the purchase of C2s, the original C cars are also referred to as C1 cars. Currently, BART operates 150 C1 cars and 80 C2 cars.
In 1995, BART contracted with ADtranz (acquired by Bombardier Transportation in 2001) to refurbish and overhaul the 439 original Rohr A- and B-cars, updating the old vintage brown fabric seats to the less-toxic and easier-to-clean

Rolling stock
The San Francisco Bay Area Rapid Transit District is a special governmental agency created by the State of California consisting of Alameda County, Contra Costa County, and the City and County of San Francisco. San Mateo County, which hosts six BART stations, is not part of the BART District as its voters opted to exclude itself in the 1960s. It is governed by an elected Board of Directors with each of the nine directors representing a specific geographic area within the BART district. BART has its own police force.
While the district includes all of the cities and communities in its jurisdiction, some of these cities do not have stations on the BART system. This has caused tensions in places like Livermore which pay BART taxes but receive no BART service. In areas like Fremont, the majority of commuters do not commute in the direction that BART would take them (many Fremonters commute to San Jose, where there is currently no BART service). This would be alleviated with the completion of a BART-to-San Jose extension project.
However, some cities and towns are near enough to cities with BART stations that residents commute via a bus or car to the nearest BART station. Emeryville, for instance, has no BART service, but has a free shuttle service, the Emery-Go-Round, that takes passengers to the nearby MacArthur station. For those wishing to drive their cars to the stations instead, many BART stations offer many kinds of parking options.

Governance
BART's initial cost was $1.6 billion, which included both the initial system and the Transbay Tube. Adjusted for inflation, this cost would be valued at $15 billion in 2004.
In 2005, BART required nearly $300 million in subsidies after fares. About 37% of the costs went to maintenance, 29% to actual transportation operations, 24% to general administration, 8% to police services, and 4% to construction and engineering. In 2005, 53% of the budget was derived from fares, 32% from taxes, and 15% from other sources, including advertising, station retail space leasing, and parking fees. BART's farebox recovery ratio of 53% is considered very high for a US public transit agency operating over such long distances with high frequency. It is often favorably compared to the ratio of the nearby Caltrain diesel commuter rail operation and is presented as an argument for an extension of BART all around the bay. However, much of it has to do with BART's fare structure, and lack of unlimited use pass.

Cost and budget
Fares on BART are comparable to those of commuter rail systems and are higher than those of most metros, especially for long trips. The fare is based on a formula that takes into account both the length and speed of the trip. A surcharge is added for trips traveling through the Transbay Tube, to San Francisco International Airport, or through San Mateo County, which is not a BART member. Historically and up until only recently, passengers have used refillable paper-plastic-composite tickets, on which fares are stored via a magnetic strip, to enter and exit the system (a similar magnetic strip ticketing system is used on the Washington Metro in Washington, D.C). The exit faregate prints the remaining balance on the ticket each time the passenger exits the station. A paper ticket can be refilled at a ticket machine, the remaining balance on any ticket can be applied towards the purchase of a new one, or a card is simply captured by the exit gate when the balance reaches zero; multiple low value cards can be combined to create a larger value card, but only at specific ticket exchange locations which are located on some BART stations.

Blue tickets – General: the most common type, includes high-value discount tickets
Red tickets – Disabled Persons and children aged 4 to 12: 62.5% discount, special ID required (children under the age of 4 ride free)
Green tickets – Seniors age 65 or over: 62.5% discount, proof of age required for purchase
Orange tickets – Student: special, restricted-use 50% discount ticket for students age 13-18 currently enrolled in high or middle school
BART Plus – special high-value ticket with 'flash-pass' privileges with regional transit agencies, including MUNI's buses.
EZ Rider – (a new plastic "smart chip" debit card program that will eventually merge with the TransLink Phase II Program in 2007) Fares
BART was one of the first US systems of any size to have substantial automated operations. The trains are computer-controlled via BART's Operations Control Center (OCC) and headquarters at Lake Merritt and generally arrive with regular punctuality. Train operators are present to make announcements, close doors, and operate the train in case of unforeseen difficulties.
As a first-generation system, BART's automation system was plagued with numerous operational problems during its first years of service. Shortly before revenue service began, an on-board electronics failure caused one empty 2-car test train, dubbed the Fremont Flyer, to run off the end of the platform at its namesake station into a parking lot, though there were no injuries.

Automation
BART has direct connections to two regional rail services – Caltrain, which provides service between San Francisco, San Jose, and Gilroy, at the Millbrae Station, and Amtrak's Capitol Corridor, which runs from Sacramento to San Jose, at the Richmond and Coliseum/Oakland Airport stations. A third Capitol Corridor connection at the Union City station is planned as part of a larger Dumbarton Rail Corridor Project to connect Union City, Fremont, and Newark to various Peninsula destinations via the Dumbarton rail bridge. which ran to eastern Alameda County and far eastern and western areas of Contra Costa County; these routes were later devolved to sub-regional transit agencies such as Tri-Delta Transit and the Livermore Amador Valley Transit Authority (WHEELS) or, in the case of Dublin/Pleasanton service, replaced by a full BART extension.
BART is connected to Oakland International Airport via AirBART shuttle buses, which bring travelers to and from the Coliseum/Oakland Airport BART station. These buses are operated by BART and accept exact-change BART fare cards in addition to exact change. BART also connects to the San Francisco International Airport, though in this case the train actually enters the airport directly and no shuttle is necessary, although connections are available to AirTrain for those not departing or arriving from the international terminal.
Other services connect to BART including the Emery Go Round (Emeryville), WestCat (north-western Contra Costa County), Benicia Transit (Benicia), Union City Transit (Union City), and the Santa Clara Valley Transportation Authority (VTA, in Silicon Valley).
The bus service connecting the University of California, Berkeley to the Berkeley BART station was once called Humphrey Go-BART, a spoonerism of the famous actor and director Humphrey Bogart. It has since been replaced by a number of regular AC Transit bus routes and shuttle bus routes operated by the university.

Connecting rail and bus transit services
BART hosts Car Sharing locations at many stations, a program pioneered by City CarShare. Riders can transfer from BART, and complete their journeys by car. BART has started to offer long-term airport parking through a third party vendor at most East Bay stations. Travelers must make an on-line reservation in advance and pay the daily fee of $5.00 before they can leave their cars at the BART parking lot.
Casual carpools have formed at North Berkeley station and the area around El Cerrito Del Norte station. The lots are convenient since most carpoolers use public transit back to their final destination. However, because of how BART charges for parking, passengers cannot park at most BART lots without paying a fare.

Other connecting services

History of BART
The idea of an underwater electric rail tube was first proposed in the early 1900s by Francis "Borax" Smith. It is no coincidence that much of BART's current coverage area was once served by the electrified streetcar and suburban train network called the Key System. This early twentieth century system once had regular trans-bay traffic across the lower deck of the Bay Bridge. By the 1950s the entire system had been dismantled in favor of automobiles and buses and the explosive growth of highway construction.
Proposals for the modern rapid transit system now in service began in 1946 by Bay Area business leaders concerned with increased post-war migration and growing congestion in the region. An Army-Navy task force concluded that an additional trans-bay crossing would soon be needed recommending a tunnel; however, it was not until the 1950s that the actual planning for a rapid transit system would begin. In 1951, California's legislature created the San Francisco Bay Area Rapid Transit Commission to study the Bay Area's long term transportation needs. The commission's 1957 final report concluded the most cost effective solution for the Bay Area's traffic woes would be to form a transit district charged with the construction and operation of a high-speed rapid rail system linking the cities and suburbs. Nine Bay Area counties were included in the initial planning commission.

Origins and planning
BART construction officially began on June 19, 1964 with President Lyndon Johnson presiding over the ground-breaking ceremonies at the 4.4 miles (7 km) test track between Concord and Walnut Creek in Contra Costa County.
The enormous tasks to be undertaken were daunting. System wide projects would include the construction of three underground rail stations in Oakland's populated downtown area, four stations through San Francisco's downtown beneath Market Street, three subterranean stations in Berkeley (which paid more to bury them, in contrast to the stations in neighboring Oakland and El Cerrito), the 3.5 miles (6 km) tunnel through the Berkeley Hills; and of course the 3.6 miles (6 km) Transbay Tube between Oakland and San Francisco beneath the San Francisco Bay. Constructed in 57 sections, The Tube is the world's longest and deepest immersed tunnel and cost $180 million. It was completed in August 1969.
Peter Hall, author of the book Great Planning Disasters, describes BART as one of the sensational planning disasters of the 20th century, alongside the Anglo-French Concorde and the Sydney Opera House.

Construction of the initial system
BART began regular passenger service on September 11, 1972, reporting more than 100,000 passengers in its first five days of operations. The Transbay Tube opened two years later on September 16, 1974, thus linking each of four branches extending to Daly City, Concord, Richmond, and Fremont.
The 1989 Loma Prieta earthquake gave BART an unequaled opportunity to shine as a star and major hero during the catastrophe. Transportation between San Francisco and Oakland was affected drastically, with the breakage of a section of the San Francisco-Oakland Bay Bridge and the near-total destruction of the Cypress Street Viaduct. With most of the Bay Area's major freeways either heavily damaged or destroyed, BART trains, within six hours of the original quake, were again operational effectively becoming the sole mode of transportation throughout the area. Even with routine service interruptions following aftershocks for inspection of tracks, over- and under-crossings, and tunnels, BART remained operational.
Expansion to the original system was made possible by a region-wide agreement under which San Mateo County was to contribute $200 million to East Bay extensions as a "buy-in" to the system without actually joining the BART district. Funds also came from many east county residents who paid into the system for bart for many years. The North-of-Concord extension opened in two phases: service to North Concord/Martinez beginning on December 16, 1995, and service to Pittsburg/Bay Point beginning a year later on December 7, 1996. The first service south of Daly City began on February 24, 1996, to Colma. A year later on May 10, 1997, service began from Bay Fair to Castro Valley and Dublin/Pleasanton.

Operation
BART has had relatively few accidents during its nearly four decades of operation. There have been no accidents attributed to brake failure. The following incidents are known to have occurred on the BART system:

In 1974, shortly after the system opened, a train, dubbed the Fremont Flyer, failed to stop at the Fremont terminus station and ran off the tracks and into the station parking lot. However, it was only a test run and carried no passengers. There were no injuries.
The tube was closed from 17 January to 4 April 1979, after a train caught fire while in the Transbay Tube, injuring dozens, killing a fireman, and damaging equipment. San Francisco International Airport extension

Future expansion and extension
An 8.7 km (5.4 mi) extension of BART southward past Fremont to the Warm Springs District in southern Fremont, with an optional station at Irvington between the Fremont and Warm Springs stations, is in the planning and engineering stage by BART planning staff. This extension received a green light from the federal government when the Federal Transit Administration issued a Record of Decision on October 24, 2006.

Warm Springs & San Jose extensions
Procurement is currently underway for a people mover that would directly connect the Coliseum station to the terminal buildings at Oakland International Airport. This connection would physically resemble the AirTrain connection to New York City's JFK Airport, in that passengers would leave standard subway cars at a nearby station and enter a specialized people mover to reach the airport itself. However, unlike the AirTrain, the Oakland Airport Connector will be operated by BART, and integrated into the BART fare system, with standard BART ticket gates located at the entrance to the station at the Airport end of the people mover. Construction of this extension is expected to start in 2007, with revenue service expected by 2011. The airport connector will provide connecting travelers that fly into SFO and out of OAK (or vice versa), the ability to make the connection exclusively by train with a single train transfer but no bus transfer.

Oakland Airport Connector
An alternative plan for extension into the communities of Antioch, eBART calls for diesel multiple unit train service to be implemented from the existing Pittsburg/Bay Point station with a cross-platform transfer east along the Highway 4 corridor to the town of Byron, with the future possibility of service to Tracy in the San Joaquin Valley. New stations would be located in Pittsburg, Antioch, Oakley, Brentwood, and Byron. Another option would be a Caltrain-like service on the existing Union Pacific right-of-way from North Concord to Brentwood and beyond to Tracy and Stockton, though such a project would be subject to problems associated with using non-dedicated rights of way. Service was expected to start in 2010 but the project has been delayed.

eBART
This extension of either conventional BART or diesel multiple unit BART service would go from Dublin/Pleasanton station east to Livermore and over the Altamont Pass into Tracy and the Central Valley along I-580. It could possibly also go north through Dublin, San Ramon, Danville, and Alamo to the existing Walnut Creek station via the I-680 corridor.
Currently, a petition to extend BART to Livermore is being circulated by Linda Jeffery Sailors, the former mayor of Dublin, California.
The extension of conventional BART rail to Tracy is considered unlikely, as San Joaquin County, in which Tracy is located, is not part of the nine district counties and does not pay into the regional BART tax. The extension of third-rail BART, which would require exclusive and grade-separated rights-of-way over such a long distance, would be orders of magnitude more expensive. With conventional rail, existing trackage can be used, and incremental upgrades (such as grade separations at selected intersections, overhead electrification, signaling improvements, utilities relocation, etc.) are possible as funding dollars become available, but choosing BART would require a full build-out of the system initially, along with comprehensive funding.

I-580/Tri-Valley Corridor
A corridor study of extending the service north from the Richmond Station is underway with numerous options being studied. One would create commuter rail service utilizing lightweight diesel multiple units (DMU) to operate on existing or new rail trackage. In order to operate on existing tracks with freight service, however, heavier-weight DMU vehicles adhering to Federal Railroad Administration regulations would need to be used. This option is known as wBART. A second option would create a commuter rail service running from the BART terminus along the Amtrak line to Hercules and possibly Fairfield and Vacaville in Solano County, similar to the Caltrain or ACE services. Yet another option would extend conventional BART to a North Richmond station near the Richmond train yard at 13th Street/Rumrill Avenue and Market Street, then continue along the existing Southern Pacific rail line and the Richmond Parkway expressway to Interstate 80. The service would have a Hilltop station and then continue along I-80 to Highway 4 in Hercules, near Hercules Transit Center. Service would continue along I-80 through Vallejo until the I-505 interchange in Vacaville. Finally, a proposed option would stretch BART westward across the Richmond-San Rafael Bridge into central Marin County.

I-80/West Contra Costa Corridor
BART planners have studied and/or planned infill stations for at least three sites within the system. Infill stations are stations constructed on existing line segments between two existing stations. Construction costs for the planned 30th Street Mission station in San Francisco between 24th Street Mission and Glen Park stations are estimated at approximately $500 million.

Infill stations
The West Dublin/Pleasanton station will be located in the median of I-580 just west of the I-680 interchange between the Castro Valley and Dublin/Pleasanton stations. Construction estimates for this station are $100 million, with funding coming from a unique public-private partnership and transit-oriented development (TOD) project on adjacent BART-owned property. Construction on the station began in October 2006, and is slated for completion in 2009.

Infill station under construction
BART, like other transit systems of the same era, endeavored to connect outlying suburbs with job centers in Oakland and San Francisco by building out lines that paralleled established commute routes of the region's freeway system. The majority of BART's service area, as measured by percentage of system length, consists of trackage in the low-density suburbs. Unlike the New York City Subway or the London Underground, individual BART lines were not designed to provide frequent service, as evidenced by the current maximum achievable headway of 13.33 minutes per line through the quadruple interlined section. Muni provides local light-rail service within San Francisco city limits and runs with smaller headways than does BART. BART could be characterized as a "commuter subway", since it has the characteristics of a commuter rail system, including lengthy lines that extend to the far reaches of suburbia with large distances between any two adjacent stations. However, in the urban areas of San Francisco and downtown Oakland, multiple lines converge, and BART takes on the characteristics of an urban subway, including short headways and transfer opportunities to other lines.
Suburban stations, particularly those in Contra Costa County, southern Alameda County, and San Mateo County are park and ride. These stations are spaced two or more miles (3 km) apart and offer free or subsidized parking; thus many lots are filled to capacity during the morning commute peak. To augment revenue, BART has begun charging for parking at selected stations. Nonetheless, it has been criticized that the parking fee is subsidized and significantly below the market-clearing price as evidenced by the capital outlays of building an individual parking space at between $15,000 and $39,000 per space. However, BART possesses all of the qualities of a true metro system, including electrified third rail propulsion, exclusive grade-separated right-of-way, frequent headway service, and pre-paid fare card access. These factors contribute to the consideration of BART as a hybrid metro-commuter system, functioning as a metro in the central business districts of San Francisco, Oakland, and Berkeley, and as commuter rail in outlying areas.

BART compared with other rail transit systems
A recent study shows that along with some Bay Area freeways, some of BART's overhead structures would collapse in the event of a major earthquake, which is predicted as highly likely to happen in the Bay Area within the next 30 years.

Recent news

Organization Management

Chief Spokesperson

List of Bay Area Rapid Transit stations
List of rapid transit systems
List of United States rapid transit systems by ridership
Noise mitigation