Bus system serving the Boston metropolitan area operated by the Massachusetts Bay Transportation Authority
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 |
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| Products | Bus transit services, including local bus routes, Silver Line BRT, express buses, and contracted suburban 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 encompasses 151 routes serving the Boston metropolitan region, coordinating seamlessly with MBTA subway lines, Commuter Rail, and additional bus networks. Among these, the MBTA directly manages 147 routes, while four are operated under contracts with private firms. Moreover, four suburban transit services receive partial financial support from the MBTA.
As of 2024, the standard one-way fare for local buses is $1.70. The Silver Line routes operating along the waterfront (SL1, SL2, SL3, SLW) charge the regular subway fare of $2.40. Express bus services apply a dual fare structure: $1.70 for local segments and $4.25 for express sections on highways.
Service levels were disrupted during the COVID-19 crisis but largely returned to pre-pandemic conditions by 2021, though some routes were not restored. Since 2018, the MBTA has been undertaking a comprehensive bus network overhaul scheduled for completion in 2028; initial modifications began rolling out in December 2024.
Silver Line
The Silver Line comprises six bus rapid transit routes promoted as rapid transit alternatives, divided into two main branches: the Waterfront routes (SL1, SL2, SL3, SLW), which run through the South Boston Transitway tunnel, and the Washington Street routes (SL4, SL5), operating on surface streets. Waterfront services charge subway fares, while Washington Street lines maintain regular bus fares. All Silver Line vehicles are 60-foot articulated buses; those serving the Waterfront are hybrid models equipped with extended battery capacity to enable electric operation within the tunnel.
The SL5 began service in 2002, replacing the Washington Street Elevated line; the Shuttle started in 2004; SL2 and SL3 also launched in 2004; SL1 commenced in 2005 utilizing dual-mode buses; SL4 was introduced in 2009 following cancellation of a proposed tunnel extension; and a new SL3 route connecting Chelsea opened in 2018.
Crosstown
The two crosstown (CT) lines offer limited-stop service linking key subway and bus transfer hubs. Initially launched with three crosstown routes in 1994 by the MBTA, route CT1 was merged into route 1 in 2019.
Routes 1–121
These numbered lines provide the bulk of local transit within Boston’s core metropolitan area; many trace their origins back to streetcar lines operated by the Boston Elevated Railway. The numbering generally follows a clockwise pattern from southeast to northeast and has remained mostly consistent since the BERy period despite some consolidations and additions under both the Metropolitan Transit Authority (M.T.A.) and MBTA administrations.
Seven of these routes— , , , , , , and —serve western suburban communities such as Bedford, Waltham, Lexington, and Needham. These originated from former Middlesex and Boston Street Railway lines acquired in 1972 and were assigned numbers that had previously been retired.
Fourteen routes— , , , , , , , , , , , , , and —were identified as key bus routes in 2004 due to their high ridership and frequent service supporting dense urban corridors alongside the subway system. Starting in 2024, the MBTA is transitioning away from the "key bus route" designation toward a broader frequent route network concept. Routes 28 and 39 operate with 60-foot articulated buses.
Additionally, four early morning round trips operate between outlying stations and over multiple local routes primarily for station agents but open to all passengers. These runs are internally numbered 191–194 and appear as variants of regular local routes in schedules.
131–137
Routes numbered 131 through 137 operate within the Melrose region, tracing their origins to former Eastern Massachusetts Street Railway services that were incorporated into the MBTA system in 1968. The now-defunct routes 136 and 137 once extended services as far as Lowell and Lawrence, which were their original endpoints. The 132 route started out under Service Bus Lines before the MBTA assumed control in 1975.
171
The 171 route functions as an early morning limited service substituting for the CT3 line following its reduction from Logan Airport in 2002. Other routes in the 170 series were brief industrial transit services.
201–202
The original 20 belt route was formed by the M.T.A. in 1962, combining BERy’s stub routes 20 and 21. In 2005, this route was split into two separate designations, routes 201 and 202, to distinguish the loop directions more clearly.
210–245
Operating in the vicinity of Quincy, Massachusetts, routes numbered from 210 to 245 originated from former Eastern Massachusetts Street Railway lines that were absorbed into the MBTA network in 1968. With the gradual launch of the Red Line's Braintree Branch during the 1970s and 1980s, these routes were adjusted to primarily terminate at rapid transit stations such as .
350–354
These lines operate in the Burlington and Woburn regions and trace their origins to the Lowell–Boston route of the Eastern Massachusetts Street Railway, which the MBTA acquired in 1968 before later shortening service to Burlington.
411–465
Serving Lynn and the North Shore, these routes include former Service Bus Lines (such as 411 and 430) acquired in 1975, alongside primarily Eastern Massachusetts Street Railway lines taken over in 1968. Weekend short-turn versions, marked with a W suffix, conclude at Wonderland station.
501–558
Connecting Newton with downtown Boston through the Massachusetts Turnpike (I-90), these express routes were launched in the 1960s to utilize the newly extended turnpike. The 500 series covers significant commuter pathways, while the 550 series developed from Middlesex and Boston Street Railway services to Newton Corner, extended into downtown during the 1960s and incorporated into the MBTA system in 1972; these routes were reduced back to Newton Corner in 2020.
Privately operated routes
Several suburban routes extending beyond the MBTA's primary service region receive partial subsidies and provide connections to MBTA transit services. The commuter lines numbered 712 through 716 were originally operated by private companies and later acquired: Rapid Transit Inc. manages routes 712 and 713, Nantasket Transportation operates route 714, and Hudson Bus Lines runs route 716.
Routes without numerical designations serve as local circulators established by municipalities with some financial support from the MBTA. These are predominantly managed by private contractors, except for the Beverly Shuttle, which is overseen by the Cape Ann Transportation Authority.
