1 (MBTA bus)

Massachusetts Bay Transportation Authority (MBTA)

Company type	Public agency
Industry	Public transportation
Founded	August 1, 1964 (1964-08-01)
Headquarters	Boston, Massachusetts , United States
Area served	Greater Boston
Products	Bus, subway, commuter rail, ferry services
Website	mbta.com

Primary bus routes within the Massachusetts Bay Transportation Authority (MBTA) network consisted of 15 lines distinguished by elevated ridership and frequency benchmarks as outlined in the 2004 MBTA Service Policy. Collectively, these routes represented roughly 40% of the MBTA's overall bus passenger volume. They offered frequent transit service throughout Boston's most densely populated neighborhoods and served as key connectors with other MBTA modes to enhance regional mobility.

Designated as integral components of the MBTA's core network, these primary bus routes appeared on updated transit maps displayed in subway stations and public venues alongside rapid transit and commuter rail services. Due to their substantial ridership, they received priority for service enhancements, including pilot late-night operations, and have been focal points in urban transportation planning and engineering research. With the introduction of the 2024 Bus Network Redesign, the designation "key bus route" is being phased out in favor of a more comprehensive network of high-frequency routes.

History

The MBTA launched an initiative in November 2006 aimed at improving service quality on its primary bus lines. The 2008 Service Plan proposed upgrades for multiple routes, notably recommending Route 31 be elevated to primary route status. This led to a $10 million Key Routes Improvement Project funded through the American Recovery and Reinvestment Act of 2009. Although the Silver Line was initially included in this effort, it was later managed as a separate undertaking. The first phase of improvements wrapped up in 2013; however, some planned enhancements remained incomplete. By June 2017, key routes demonstrated greater schedule adherence compared to other lines—achieving 75% reliability versus 61%.

A study conducted in 2012 revealed that proximity to primary bus routes correlated with fewer taxi trips, suggesting that only those routes with the highest frequency effectively rivaled taxi services.

In April 2014, an extended late-night service pilot commenced on key bus and rapid transit lines for one year, contingent upon ridership levels and sponsorship support. However, by April 2015, operating hours were reduced and some routes discontinued extended service; ultimately, late-night service ceased entirely in March 2016.

Primary bus routes were highlighted within Boston Mayor Marty Walsh’s "Go Boston 2030" plan, which aimed to ensure all residents lived within a ten-minute walk from either a T station or a primary bus stop. The plan also proposed a new key route linking the Longwood Medical Area with JFK/UMass through Roxbury.

In May 2022, the MBTA unveiled a draft Bus Network Redesign proposing modifications to most primary routes and upgrading several others to create an expanded high-frequency network complementing rapid transit services. A revised proposal was released in November 2022.

Criteria for primary routes

According to the MBTA’s Service Delivery Policy, primary bus routes are identified based on five factors:

• Elevated passenger demand
• Integration within the transit system
• Geographic reach
• Support for significant new developments
• Operation as bus rapid transit

Service standards

Primary routes are required to maintain superior service span and frequency compared to regular local routes.

Route Category	Minimum service span
Local	Weekdays	7:00 AM – 6:30 PM
	Saturdays	8:00 AM – 6:30 PM
	Sundays	10:00 AM – 6:30 PM
Primary	Weekdays	6:00 AM – Midnight
	Saturdays	6:00 AM – Midnight
	Sundays	7:00 AM – Midnight

Route Category	Minimum service frequency
Local	Morning & evening peak periods	Every 30 minutes
	Other times	Every 60 minutes
	Weekend days	Every 60 minutes
Primary	Morning & evening peak periods	Every 10 minutes
	Midday hours	Every 15 minutes
	Evenings and weekends	Every 20 minutes

Route list

The MBTA identified 15 principal routes: 1, 15, 22, 23, 28, 32, 39, 57, 66, 71, 73, 77, 111, 116, and 117. These corridors have been prioritized in public and official appeals for improved limited-stop or express services to enhance operational efficiency and address substantial ridership demand.

1

The 1 Harvard Square–Nubian Station line links Cambridge with Roxbury and originated in September 1962 through the consolidation of two routes that previously divided at Massachusetts Avenue (currently Hynes Convention Center): the 76 Harvard–Massachusetts station and the 47 Massachusetts station–Dudley. In May 1987, the alignment was altered to divert southeast from Washington Street onto Albany Street and Melnea Cass Boulevard to provide service to Boston Medical Center. The route predominantly follows Massachusetts Avenue, beginning at Harvard, passing the Massachusetts Institute of Technology, crossing the Charles River via the Harvard Bridge into Boston, continuing past the Berklee College of Music to Boston Medical Center, then heading southwest toward Nubian station through Albany Street and Melnea Cass Boulevard.

By 2015, Cambridge had plans to introduce signal priority for route 1 at selected intersections. The MBTA's May and November 2022 network proposals did not include any modifications to this route.

In October 2023, transit advocacy organization Transitmatters identified the 1 bus as the MBTA’s slowest and most congested route, reporting an average speed of just 6.55 mph alongside a bunching rate of 17.7%, reflecting notable challenges in service reliability.

15

The 15 Fields Corner Station or St. Peter's Square–Ruggles Station route originates at St. Peter's Square in northern Dorchester, proceeding north along Bowdoin Street, west on Hancock Street, then north on Columbia Street toward Uphams Corner. It continues westward on Dudley Street to Nubian station, then follows Malcolm X Boulevard west before heading north on Tremont Street to reach Ruggles station. During nights and weekends, service terminates at Fields Corner station, operating via Geneva Avenue and Bowdoin Street back to St. Peter's Square.

On April 6, 1962, buses replaced trackless trolleys on the former 15 Kane Square–Dudley route via Uphams Corner and Dudley Street. Following the Orange Line’s relocation to the Southwest Corridor in May 1987, this route was extended to Ruggles. Service from Kane Square was further extended to St. Peter's Square on August 25, 2024.

The draft network plan released in May 2022 suggested extending this line westward to Oak Square, substituting for route , thereby creating an Oak Square–Fields Corner connection. However, the November 2022 draft plan revised this proposal by truncating the route back to Ruggles and maintaining route 65 as a separate service.

22

The 22 Ashmont Station–Ruggles Station via Talbot Ave operates from Ashmont northwest toward the former location of Egleston station, then travels north along Columbus Avenue and Tremont Street, paralleling the Orange Line corridor before terminating at Ruggles.

This route transitioned from trackless trolley service to buses on April 6, 1962; initially designated as the 22 Ashmont–Dudley via Talbot and Warren with its endpoint at . After the Orange Line moved to the Southwest Corridor in May 1987, the route was extended to Ruggles. Both draft network plans from May and November of 2022 proposed relocating the inner terminal to Longwood Medical Area.

23

The 23 Ashmont Station–Ruggles Station via Washington Street route shares its terminal points with route 22 but follows an alternate course. Beginning at Ashmont on Talbot Avenue, it heads north along Washington Street, then continues onto Warren Street reaching Nubian station. From Nubian, the bus travels westward via Malcolm X Boulevard to Roxbury Crossing, then proceeds north on Tremont Street to arrive at Ruggles.

This line transitioned from trackless trolleys to buses on April 7, 1962, originally designated as 22 Ashmont–Dudley via Washington Street and Warren. With the Orange Line relocation in May 1987, the route extended service to Ruggles. A study conducted in 2017 identified overcrowding challenges on routes 23 and 28, suggesting that enhancing route 29 could alleviate these pressures. Beginning March 1, 2022, a city-sponsored fare-free initiative covers routes 23, 28, and 29, continuing through February 28, 2026. The network redesign proposals released in May and November 2022 did not include any modifications to this route.

28

The 28 Mattapan Station–Ruggles Station line connects the Mattapan and Grove Hall neighborhoods along Blue Hill Avenue, a principal transit corridor. Historically, Blue Hill Avenue was a heavily trafficked transit route; for example, in 1945 the route 29 Mattapan–Egleston operated with headways as short as 1.5 minutes during morning rush hours. Streetcars once ran on exclusive rights-of-way until they were gradually integrated into mixed traffic between 1940 and 1950, with bus service replacing streetcars by 1955. The bus network restructuring in 1987 introduced route 28 as a supplement to route 29; by December 1989, route 28 became the dominant line on Blue Hill Avenue while route 29 was restricted to peak-hour service terminating at Jackson Square. Passenger shelters were installed at stops in 2001. Additionally, from December 2006 until June 2010, morning peak short-turn trips operated as route 25 between Franklin Park and Dudley (later extended to Ruggles).

The 2003 Program for Mass Transportation (PMT) explored several potential Silver Line expansions; a bus rapid transit (BRT) overlay for route 28 was briefly reconsidered in the Silver Line Phase III plans of 2006. In 2009, the state proposed the 28X, a limited-stop BRT service along New England’s busiest bus corridor featuring dedicated lanes and queue jump signals. The $114 million initiative aimed to begin construction in April 2010 with service commencing in early 2012.

However, significant community opposition arose due to inadequate local engagement, concerns over parking loss and removal of median strips, and anticipated long-term construction impacts. Consequently, the state withdrew the proposal late in 2009. In June 2010, the MBTA introduced articulated 60-foot buses on route 28 to boost capacity; this change sparked resident worries about stop eliminations in the steep Grove Hall area. The Roxbury–Dorchester–Mattapan Transit Needs Study of 2012 recommended implementing the express-style service of the proposed 28X without constructing new infrastructure.

In August 2020, Boston and the MBTA jointly applied for $15 million in federal funds toward a $30 million Blue Hill Avenue improvement project that included center-running bus lanes aimed for completion by the end of 2021; this application was denied in September. A subsequent $25 million funding request was submitted in July 2021. Between August 2021 and February 2022, a $500,000 pilot funded by city American Rescue Plan resources offered free fares and all-door boarding on route 28 to reduce delays along this frequently congested corridor. Following this pilot, a city-funded fare-free program covering routes 23, 28, and 29 began in March 2022 and extends through February 2026. In November 2021, Boston secured a $15 million federal grant contributing toward the $39.5 million Blue Hill Avenue reconstruction project.

The network redesign proposals released in May and November of 2022 suggested extending route 28 from Roxbury Crossing toward the Longwood Medical Area while eliminating service between Roxbury Crossing and Ruggles. In February 2024, Boston announced plans for a $44 million Blue Hill Avenue reconstruction featuring center bus lanes with construction expected to commence in 2026.

32

The 32 Wolcott or Cleary Square–Forest Hills Station line follows Hyde Park Avenue, connecting Forest Hills to Readville and serving the neighborhoods of Jamaica Plain, Roslindale, and Hyde Park. Throughout its entire length, it runs parallel to the commuter rail tracks between Forest Hills and Readville.

Originally a trolley route between Forest Hills and Cleary Square until 1953, Route 32 transitioned to trackless trolley operation thereafter. By 1958, all trackless trolley services south of Forest Hills were replaced with diesel bus operations. A turnaround loop for the trackless trolleys was situated at the intersection of Hyde Park Avenue and Pine Street.

In 1981, Route 31, which ran from Mattapan Square to Wolcott Square, was combined with Route 32 at Cleary Square, creating the extended Route 32 Forest Hills–Wolcott Square. Additionally, Route 50 was adjusted to serve the Summer Street Elderly Housing area. The May and November 2022 MBTA network proposals did not suggest any modifications for this route.

39

The 39 Forest Hills Station–Back Bay Station route took over service previously provided by the Green Line E branch from Heath Street to Arborway in December 1985. It parallels the Green Line corridor between Heath Street and Copley and offers connections to both the Orange Line and commuter rail at either terminus, with Amtrak service accessible at Back Bay.

Route 39 was notable as the first MBTA line to consistently deploy articulated buses, a feature later adopted on other routes such as the 28 in late 2005. By 2013, it ranked as Boston’s second busiest bus service. Its substantial ridership contributed to the expansion of Forest Hills station during the Casey Arborway reconstruction project.

The initial May 2022 draft plan proposed extending Route 39 through several new stops while replacing segments of other routes and discontinuing service between Longwood Avenue and Back Bay. However, the November 2022 revision restored Route 39 to its existing path, instead increasing frequency on Route 47 and extending it to Union Square in Somerville.

57

Serving Boston, Newton, and Watertown, the 57 Watertown Yard–Kenmore Station route replaced the Green Line A branch after its discontinuation in 1969. This route formerly operated limited-stop service within Boston—specifically avoiding pickups along Commonwealth Avenue between Packard's Corner and Kenmore—but this practice ended in December 2006. No alterations were included for this route in either the May or November 2022 network proposals.

66

The 66 Harvard Square–Nubian Station via Allston route, once a trolley line, begins at Nubian Square in Roxbury and crosses the Southwest Corridor Park at Roxbury Crossing. It briefly parallels both Route 39 and the Green Line E branch from Brigham Circle up to Boston’s city boundary. Traveling along Harvard Street, it serves Brookline and Allston neighborhoods, detouring through Union Square (Allston) before proceeding via Cambridge Street and North Harvard Street to Harvard Square in Cambridge. This route links several transit hubs: Nubian station (Silver Line), Roxbury Crossing (Orange Line), Fenwood Road, Mission Park, Riverway (Green Line E branch), Brookline Village (Green Line D branch), Coolidge Corner (Green Line C branch), Harvard Avenue (Green Line B branch), and Harvard (Red Line). The May and November 2022 network plans did not propose any changes for this line. In August 2024, northbound trips were rerouted through the Harvard Bus Tunnel.

71

The 71 Watertown Square–Harvard station route originates at the lower level of the Harvard bus tunnel, proceeds south onto Mount Auburn Street, then continues westward into Watertown, concluding at Watertown Square.

At Harvard, buses complete their turnaround by exiting the tunnel and looping through Massachusetts Avenue, Garden Street, and Waterhouse Street. Meanwhile, at Watertown Square, a dedicated private right-of-way loop is used for turning vehicles and boarding passengers.

Streetcar operations on the 71 ceased on September 4, 1958, with trackless trolleys taking over until March 13, 2022. In 2017, routes 71 and 73 were chosen to participate in a bus rapid transit pilot initiative.

Together with routes and , routes 71 and 73 maintained trackless trolley service longer than any other MBTA lines, representing the final chapter of Boston’s historic trackless trolley system before transitioning to diesel buses in March 2022. The network redesigns proposed in May and November 2022 did not suggest any alterations to these routes. Nevertheless, plans in Watertown include a minor extension of route 71 to Watertown Yard as part of a broader reconfiguration of Watertown Square.

73

The 73 Waverley Square–Harvard Station route begins within the Harvard bus tunnel and shares Mount Auburn Street with route 71 through Cambridge and Watertown. It then diverges onto Belmont Street—which forms the boundary between Belmont and Watertown—continues along Trapelo Road in Belmont, and terminates at Waverley Square. A loop at the Waverley commuter rail station on the Fitchburg Line facilitates vehicle turnaround.

Originally operated by streetcars until the mid-1950s, route 73 began transitioning to trackless trolleys starting with short-turn trips in 1957 and completed full conversion by 1958. Trackless trolley service lasted until March 13, 2022. The May and November 2022 network proposals did not include any route modifications.

77

The 77 Arlington Heights–Harvard Station line connects Arlington with Harvard station via Massachusetts Avenue. Prior to the Red Line Northwest Extension during the 1980s, routes 77 and 77A were dominant transit options northwest of Harvard, with streetcars running at intervals under one minute during peak periods in 1945. Route 77 transitioned to diesel buses in 1955; meanwhile, route 77A converted to trolleybus operation in 1958 to release streetcars for the Highland branch conversion and eliminate boarding islands to improve traffic flow for automobiles. Route 77A provided local service south of the carhouse while route 77 operated as a limited-stop service; between 1998 and 2005, route 77 mostly supplanted route 77A, which was ultimately discontinued in 2022. In 2017, Arlington pursued private funding to implement transit signal priority, queue jump lanes, and potential bus lanes along its segment. No changes were proposed for this route in either the May or November 2022 network plans.

111

The 111 Woodlawn–Haymarket Station line connects downtown Boston with Chelsea by way of the Bill Russell Bridge and Tobin Bridge. Initially a streetcar service running between Chelsea Square and Woodlawn acquired by the Boston Elevated Railway in 1936, it was replaced by bus service later that same year. The line was extended to Haymarket in April 1975 following the closure of the Charlestown Elevated, with partial extensions beyond Woodlawn introduced in January 2001. Service beyond Woodlawn ended in September 2019; short-turn trips at Cary Square were replaced by Woodlawn trips as of December 2021. The 111 ranks among the MBTA’s most frequent numbered bus routes, operating at five-minute intervals during peak hours. No adjustments were proposed for this route in either the May or November 2022 network redesigns.

116/117

The 116 Wonderland Station–Maverick Station via Revere Street and 117 Wonderland Station–Maverick Station via Beach Street routes connected East Boston, Chelsea, and Revere. While both lines shared the majority of their paths through East Boston and Revere, they diverged only in the vicinity of Wonderland. According to the transit network proposals from May and November 2022, route 117 was planned for elimination, with the section between Broadway and Wonderland station reassigned as an extension of route 116 to preserve essential bus service frequency. This adjustment was implemented on December 15, 2024.

See also

• List of MBTA bus routes
• MBTA crosstown bus routes
• MBTA Silver Line (previously included in major routes)
• Free public transport in Boston

External links

• MBTA – routes , , , , , , , , , , , , , ,
• MBTA - Key Bus Route Improvement Program