Bus system serving the Boston metropolitan area
Massachusetts Bay Transportation Authority (MBTA) Bus System| Company type | Public transit agency |
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| Industry | Public transportation |
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| Headquarters | Boston , United States |
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Area served | Boston metropolitan region, Massachusetts |
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| Products | Bus services, including local routes, Silver Line BRT, express routes |
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| Parent | Massachusetts Bay Transportation Authority (MBTA) |
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| Website | www.mbta.com/bus |
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The Massachusetts Bay Transportation Authority (MBTA) bus system manages 151 routes throughout the Boston metropolitan region in Massachusetts. Each route provides connections to the MBTA subway network, Commuter Rail lines, or other MBTA bus services. A number of these routes trace their origins back to streetcar lines operated by the Boston Elevated Railway or to suburban transit companies such as the Eastern Massachusetts Street Railway and Middlesex and Boston Street Railway. Of the total routes, the MBTA operates 147 directly, while four are managed by private contractors. Additionally, four suburban routes receive partial financial support from the MBTA.
As of 2024, the one-way fare for local bus rides is set at $1.70. The Silver Line routes serving the waterfront (SL1, SL2, SL3, and the SLW shuttle during peak hours) apply the standard subway fare of $2.40. Express bus services charge the local fare for portions within community zones and impose a $4.25 fare for segments on express highways.
Service levels were significantly affected by the COVID-19 pandemic but were mostly reinstated by 2021, although some routes were permanently discontinued. Since 2018, the MBTA has been developing a comprehensive redesign of its bus network, with full implementation expected by 2028. The first phase of this transformation commenced in December 2024.
Silver Line
The Silver Line is a bus rapid transit (BRT) system consisting of six routes and is promoted as a rapid transit option. It operates two distinct branches: the Waterfront service (SL1, SL2, SL3, plus the rush-hour SLW shuttle), which utilizes the South Boston Transitway tunnel, and the Washington Street service (SL4 and SL5), which runs along surface streets. Fares on Waterfront routes correspond to subway pricing, whereas Washington Street routes charge standard bus fares. All Silver Line vehicles are articulated buses measuring 60 feet in length; those serving the Waterfront are hybrid models equipped with extended battery capacity to operate electrically within tunnels.
The SL5 route was introduced in 2002 as a replacement for the Washington Street Elevated line. The Shuttle service began in 2004 alongside the original SL2 and SL3 routes; SL1 followed in 2005 using dual-mode buses capable of operating on both diesel and electric power. The SL4 route was added in 2009 after plans for Phase III of the tunnel project were canceled. In 2018, a new SL3 route connecting to Chelsea was launched.
Crosstown
Two crosstown (CT) routes provide limited-stop service that links key subway stations and major bus transfer points across Boston. Initially, three crosstown lines were introduced by the MBTA in 1994; however, route CT1 was merged into route 1 in 2019.
1–121
These routes constitute the core of local transit within Boston's metropolitan center, many having their roots in the streetcar lines once operated by the Boston Elevated Railway. Arranged roughly in a clockwise sequence from the southeast to the northeast, these routes have largely preserved their numbering and paths since the BERy period, continuing through the Metropolitan Transit Authority era and into MBTA management.
Seven specific routes—, , , , , , and —serve communities in the western suburbs such as Bedford, Waltham, Lexington, and Needham. These lines originated from the 1972 acquisition of Middlesex and Boston Street Railway routes and were subsequently renumbered to reflect that transition.
In 2004, fourteen routes—including , , , , , , , , , , , , , and —were identified as key bus routes due to their high ridership. These services provide frequent connections that complement subway operations by linking Boston’s most densely populated neighborhoods. With the MBTA’s Bus Network Redesign initiative beginning in 2024, the key route designation is being phased out in favor of a more comprehensive frequent route network. Notably, routes 28 and 39 operate with 60-foot articulated buses.
Four early-morning round trips (routes 191–194) run between outlying stations and station, primarily intended to serve station agents but available to all riders. These trips are composed of segments from multiple local routes.
131–137
The Melrose region is served by routes numbered 131 through 137, which trace back to former Eastern Massachusetts Street Railway lines absorbed into the MBTA system in 1968. Routes 136 (now discontinued) and 137 once extended briefly to Lowell and Lawrence under MBTA operation. Route 132 began as a Service Bus Lines route before transitioning to MBTA control in 1975.
171
Route 171 provides limited early morning service, functioning as a replacement for the truncated CT3 airport route since 2002. Other routes in the 170 series were short-lived services catering to industrial zones.
201–202
Originally formed in 1962 by the M.T.A. from the 20 and 21 stubs of BERy, the 20 belt route was renamed in 2005 as routes 201 and 202 to better distinguish the directions of the loops.
210–245
Routes numbered 210 through 245 operate within the Quincy region and are based on former lines from the Eastern Massachusetts Street Railway that were integrated into the MBTA system in 1968. Following the gradual launch of the Red Line's Braintree Branch during the 1970s and 1980s, these routes were adjusted to primarily end at Quincy Center and other rapid transit stations.
350–354
Serving Burlington and Woburn, these routes trace their origins back to the Eastern Massachusetts Street Railway’s Lowell–Boston line, which the MBTA took over in 1968. Over time, service was shortened to end in Burlington.
411–465
Serving Lynn and the North Shore area, these routes include former Service Bus Lines (411, 430) acquired in 1975, along with predominantly Eastern Massachusetts Street Railway routes taken over in 1968. Weekend short-turn versions, indicated by a W suffix, conclude their trips at Wonderland station.
501–558
These express services link Newton with downtown Boston utilizing the Massachusetts Turnpike (I-90). Established in the 1960s alongside the turnpike extension, the 500 series includes former Middlesex and Boston Street Railway lines (notably the 550 series), which were extended into downtown Boston during that decade and incorporated into the MBTA system in 1972. Some routes were shortened back to Newton Corner in 2020.
