23 (MBTA bus)

Massachusetts Bay Transportation Authority (MBTA)

File:MBTA logo.svg Logo of the Massachusetts Bay Transportation Authority
Company type	Public agency
Industry	Public transportation
Founded	August 3, 1964 (1964-08-03)
Headquarters	Boston, Massachusetts , United States
Area served	Greater Boston area
Products	Bus, subway, commuter rail, ferry services
Owner	Commonwealth of Massachusetts
Website	www.mbta.com

Primary bus routes operated by the Massachusetts Bay Transportation Authority (MBTA) comprised 15 lines identified in the 2004 MBTA Service Policy for their elevated ridership and frequent service. Collectively, these routes represented approximately 40% of the MBTA’s total bus boardings. Serving Boston's most densely populated neighborhoods, they also provided vital connections to other MBTA modes, enhancing regional transit accessibility.</ref>

Designated as part of the MBTA’s foundational network, these primary bus routes were highlighted on updated transit maps alongside rapid transit and commuter rail services. This classification influenced targeted service enhancements such as late-night service pilots and attracted attention from urban planners and transportation engineers. With the introduction of the 2024 Bus Network Redesign, the "key bus route" label is being replaced by a more comprehensive high-frequency network concept.

History

In November 2006, the MBTA embarked on initiatives to improve service quality along these primary bus corridors. The 2008 Service Plan proposed upgrades including promoting route 31 to meet key route criteria. Subsequently, a $10 million Key Routes Improvement Project was launched, partially funded through the American Recovery and Reinvestment Act of 2009. While initially encompassing the Silver Line, that service was later managed separately. The project concluded in 2013, though some planned improvements remained incomplete. By mid-2017, key routes achieved a higher on-time performance rate (75%) compared to other routes (61%).

A study conducted in 2012 revealed that areas near key bus routes experienced reduced demand for taxi trips, indicating these frequent services effectively competed with taxis among discretionary riders.

In April 2014, extended late-night operations on key bus and rapid transit lines commenced as a one-year pilot program dependent on ridership levels and sponsorship support. However, by April 2015, service hours were curtailed and late-night operations discontinued on five key routes. Complete termination of late-night service followed in March 2016.

The key bus routes were integral to Boston mayor Marty Walsh’s "Go Boston 2030" plan, which aimed to ensure that all residents have access within a ten-minute walk to either a T station or a key bus stop. A new key route was proposed to connect the Longwood Medical Area with JFK/UMass through Roxbury.

In May 2022, the MBTA unveiled a draft plan for redesigning the bus network that suggested modifications to most key routes and upgrading additional lines to establish a unified high-frequency network complementing rapid transit services. An updated proposal was released in November 2022.

Criteria for Key Routes

According to the MBTA's Service Delivery Policy, inclusion in the Key Bus Routes program requires meeting five criteria:

• Elevated ridership demand
• Integration within the transit system
• Coverage of significant geographic areas
• Support for major new development projects
• Operation as bus rapid transit

Service Standards

Key bus routes are held to more rigorous standards than typical local routes regarding both service hours and frequency. The following tables outline these minimum requirements.

Route Type	Minimum Span of Service
Local	Weekdays	7:00 AM – 6:30 PM
	Saturdays	8:00 AM – 6:30 PM
	Sundays	10:00 AM – 6:30 PM
Key	Weekdays	6:00 AM – Midnight
	Saturdays	6:00 AM – Midnight
	Sundays	7:00 AM – Midnight

Route Type	Minimum Frequency of Service
Local	Peak periods (AM & PM)	Every 30 minutes
	Off-peak times	Every 60 minutes
	Weekends (Sat & Sun)	Every 60 minutes
Key	Peak periods (AM & PM)	Every 10 minutes
	Midday hours	Every 15 minutes
	Evenings and weekends	Every 20 minutes

Route list

The MBTA has designated 15 essential routes for targeted enhancements: 1, 15, 22, 23, 28, 32, 39, 57, 66, 71, 73, 77, 111, 116, and 117. These corridors were selected due to their substantial ridership and strategic importance. Both public officials and transit users have called for the introduction of limited-stop or express services along these lines to boost operational efficiency and improve overall service quality.

1

The 1 Harvard Square–Nubian Station line connects Cambridge with Roxbury and was formed in September 1962 by combining two earlier routes that had previously split at Massachusetts Avenue (currently Hynes Convention Center): the 76 Harvard–Massachusetts station and the 47 Massachusetts station–Dudley route. In May 1987, its path was rerouted off Washington Street southeastward onto Albany Street and Melnea Cass Boulevard to provide service to Boston Medical Center. Today, the route predominantly follows Massachusetts Avenue, beginning at Harvard, passing the Massachusetts Institute of Technology, crossing the Charles River via the Harvard Bridge, traveling through Boston near the Berklee College of Music, stopping at Boston Medical Center, then continuing southwest to Nubian station along Albany Street and Melnea Cass Boulevard.

In 2015, Cambridge proposed implementing signal priority at select intersections on this route to enhance travel times. No modifications were included in the May or November 2022 network proposals.

According to Transitmatters in October 2023, the 1 bus was identified as the slowest MBTA bus line with an average speed of just 6.55 mph and exhibited the highest rate of bus bunching at 17.7%, highlighting significant challenges in maintaining reliable service.

15

The 15 Fields Corner Station or St. Peter's Square–Ruggles Station route begins at St. Peter's Square (also known as Coppens Square) in northern Dorchester. It proceeds north along Bowdoin Street, turns west onto Hancock Street, then continues north on Columbia Street to reach Uphams Corner. From there, it travels west on Dudley Street toward Nubian station, then heads west on Malcolm X Boulevard before turning north on Tremont Street to arrive at Ruggles station. During nights and weekends, service terminates at Fields Corner station, running via Geneva Avenue and Bowdoin Street back to St. Peter's Square.

On April 6, 1962, buses replaced the former trackless trolleys operating on the 15 Kane Square–Dudley route via Uphams Corner and Dudley Street. The relocation of the Orange Line to the Southwest Corridor in May 1987 led to an extension of this route reaching Ruggles. On August 25, 2024, service from Kane Square was extended slightly northward to St. Peter's Square.

The draft network plan released in May 2022 suggested extending this route westward to Oak Square, thereby replacing route , and creating a new Oak Square–Fields Corner corridor. However, by November 2022, the plan was revised to truncate the route back to Ruggles while keeping route 65 separate.

22

The 22 Ashmont Station–Ruggles Station via Talbot Ave operates from Ashmont heading northwest toward the former site of Egleston station. It then continues north along Columbus Avenue and Tremont Street, running roughly parallel to the Orange Line before terminating at Ruggles.

This line transitioned from trackless trolley service to buses on April 6, 1962. Initially designated as route 22 Ashmont–Dudley via Talbot and Warren, it extended all the way to Dudley Square via Warren Street. Following the Orange Line’s relocation in May 1987, its terminal was extended to Ruggles. The network proposals from May and November 2022 recommended altering its inner terminal point to Longwood Medical Area.

23

The 23 Ashmont Station–Ruggles Station via Washington Street route shares its terminals with route 22 but travels a distinct course. Beginning at Ashmont on Talbot Avenue, it heads north along Washington Street, proceeds onto Warren Street toward Nubian station, then moves west along Malcolm X Boulevard to reach Roxbury Crossing, and finally turns north on Tremont Street to arrive at Ruggles.

Trackless trolleys were replaced by buses on this line as of April 7, 1962. The route was extended to Ruggles in May 1987 following the Orange Line relocation. A study conducted in 2017 found that extending and enhancing service on route 29 could alleviate overcrowding on routes 23 and 28. Between March 1, 2022, and February 28, 2026, a city-sponsored fare-free initiative applies to routes 23, 28, and 29. No modifications for route 23 were included in the transit network proposals released in May or November of 2022.

28

The 28 Mattapan Station–Ruggles Station line serves the neighborhoods of Grove Hall and Mattapan along Blue Hill Avenue, a key arterial route. Blue Hill Avenue historically featured streetcar service with peak intervals as short as 1.5 minutes in 1945; buses replaced streetcars by 1955. Established in 1987 to complement route 29, route 28 became the main service on Blue Hill Avenue by 1989. Passenger shelters were installed in 2001, and from 2006 to 2010, short-turn peak trips operated under the designation route 25.

In 2003, multiple expansions of the Silver Line were evaluated, including a bus rapid transit (BRT) overlay for route 28. The state introduced plans for the 28X limited-stop BRT in 2009 to accommodate heavy ridership along the corridor, envisioning dedicated bus lanes and queue jump lanes with an estimated cost of $114 million. Construction was planned for 2010 with service anticipated to begin by 2012; however, community concerns regarding parking reductions and construction impacts led to the project's cancellation later that year.

In June 2010, the MBTA upgraded route 28 vehicles to articulated 60-foot buses to boost capacity, which necessitated removing several stops in Grove Hall due to vehicle length constraints. A transit study from 2012 recommended launching the 28X as an express service without additional infrastructure improvements.

In August 2020, the MBTA and City of Boston jointly sought $15 million in federal funds toward a $30 million Blue Hill Avenue enhancement project featuring center-running bus lanes targeted for completion by late 2021; this funding request was denied. A subsequent $25 million federal grant application was submitted in July 2021. From August 2021 through February 2022, a city-supported pilot program implemented fare-free rides and all-door boarding on route 28 to shorten travel times. Fare-free service continues on routes 23, 28, and 29 from March 2022 through February 2026 under city funding. In November 2021, Boston secured a $15 million federal grant contributing toward a $39.5 million Blue Hill Avenue reconstruction effort.

Transit network proposals issued in May and November of 2022 suggest extending route 28 from Roxbury Crossing into the Longwood Medical Area while discontinuing the segment between Roxbury Crossing and Ruggles. In February 2024, Boston announced plans for a $44 million Blue Hill Avenue rebuild incorporating center bus lanes, with construction expected to commence in 2026.

32

The 32 Wolcott or Cleary Square–Forest Hills Station line operates along Hyde Park Avenue, connecting Forest Hills to Readville and serving the neighborhoods of Jamaica Plain, Roslindale, and Hyde Park. This route runs adjacent to the commuter rail tracks throughout its entire length.

Originally a trolley line running from Forest Hills to Cleary Square until 1953, Route 32 transitioned to trackless trolley operation thereafter. By 1958, diesel buses replaced the trackless trolleys on the segment south of Forest Hills. A dedicated turnaround loop for trackless trolley vehicles was situated at the intersection of Hyde Park Avenue and Pine Street.

In 1981, Route 31, which ran between Mattapan Square and Wolcott Square, was consolidated with Route 32 at Cleary Square, creating the combined Route 32 Forest Hills–Wolcott Square. Meanwhile, Route 50 was adjusted to provide service to the Summer Street Elderly Housing Area. No modifications were suggested for this route in the network proposals released in May and November 2022.

39

The 39 Forest Hills Station–Back Bay Station line took over from the Green Line E branch service between Heath Street and Arborway starting in December 1985. It parallels the Green Line corridor from Heath Street to Copley and provides connections to both the Orange Line and commuter rail at either terminus, including Amtrak services at Back Bay station.

Route 39 was notable as the first MBTA route to regularly deploy articulated buses beginning in late 2005; this bus type was subsequently introduced on other lines such as Route 28. By 2013, it ranked as Boston’s second busiest bus route. The high passenger volume on Route 39 influenced expansion efforts at Forest Hills station during the Casey Arborway reconstruction project.

The draft network plan published in May 2022 suggested extending Route 39 through via and , substituting portions of routes , , and , while eliminating service between Longwood Avenue and Back Bay. However, the November 2022 draft reversed these changes, retaining the existing routing and instead proposing increased frequency on Route 47 with an extension to Union Square.

57

The 57 Watertown Yard–Kenmore Station line serves the cities of Boston, Newton, and Watertown. It was introduced as a replacement for the Green Line A branch after its discontinuation in 1969. Historically, Route 57 operated limited-stop service within Boston by bypassing passenger pickups along Commonwealth Avenue between Packard's Corner and Kenmore Square; this limited-stop pattern was discontinued in December 2006. The May and November 2022 network plans did not recommend any alterations to this route.

66

The 66 Harvard Square–Nubian Station via Allston route, once a trolley line, begins at Nubian Square in Roxbury and crosses over the Southwest Corridor Park near Roxbury Crossing station. It shares portions of its path with both Route 39 and the Green Line E branch between Brigham Circle and Boston’s city boundary. Following Harvard Street, it serves Brookline and Allston neighborhoods before diverting through Union Square (Allston). The route then continues along Cambridge Street and North Harvard Street to conclude at Harvard Square in Cambridge.

This corridor links several major transit nodes including 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 station (Red Line). No changes were proposed for Route 66 in either the May or November 2022 network drafts. In August 2024, northbound trips were rerouted through the Harvard Bus Tunnel to improve service flow.

71

The 71 Watertown Square–Harvard station route originates from the lower level of the Harvard bus tunnel, proceeding southward onto Mount Auburn Street before continuing west into Watertown, where it concludes at Watertown Square.

At Harvard, buses reverse direction by leaving the tunnel and navigating a loop along Massachusetts Avenue, Garden Street, and Waterhouse Street prior to returning. At its Watertown terminus, the route utilizes a dedicated right-of-way loop designed for turning around and passenger boarding.

Streetcar operations on route 71 ceased on September 4, 1958, succeeded by trackless trolley service until March 13, 2022. In 2017, routes 71 and 73 were chosen to participate in a bus rapid transit pilot initiative.

Together with neighboring routes , and , routes 71 and 73 maintained trackless trolley service well beyond the phase-out of other MBTA lines, representing the last segment of Boston’s historic trolleybus system before converting to diesel buses in March 2022. The 2022 network proposals did not suggest alterations to this route; however, Watertown intends a minor extension to Watertown Yard as part of an upcoming reconfiguration of Watertown Square.

73

The 73 Waverley Square–Harvard Station route also begins within the Harvard bus tunnel and shares Mount Auburn Street with route 71 through Cambridge and Watertown. It then proceeds along Belmont Street—serving as the boundary between Belmont and Watertown—and continues via Trapelo Road to terminate at Waverley Square. The route loops around the Waverley commuter rail station on the Fitchburg Line.

Initially served by streetcars until the mid-1950s, this line transitioned to trackless trolley service beginning with short-turn operations in 1957 and full conversion by 1958. Trackless trolleys continued running until March 13, 2022. The May and November 2022 network plans proposed no modifications to this route.

77

The 77 Arlington Heights–Harvard Station links Arlington with Harvard station via Massachusetts Avenue. Prior to the Red Line Northwest Extension in the 1980s, routes 77 and 77A were the primary transit options northwest of Harvard, with combined streetcar frequencies reaching less than one minute during peak periods in 1945. Route 77 transitioned to diesel buses in 1955; meanwhile, route 77A switched to trolleybuses in 1958 to free streetcars for the Highland branch conversion and eliminate boarding islands to improve automobile traffic flow. Route 77A handled all local stops south of the carhouse while route 77 operated as a limited-stop service; however, between 1998 and 2005, route 77 largely supplanted route 77A, which was fully discontinued in 2022. In 2017, Arlington pursued private funding for implementing signal priority, queue jumps, and potential bus lanes along its portion of the route. No changes were included for this line in the May or November 2022 network proposals.

111

The 111 Woodlawn–Haymarket Station provides transit between downtown Boston and Chelsea via the Bill Russell Bridge and Tobin Bridge. Originally run as streetcars connecting Chelsea Square to Woodlawn under Boston Elevated Railway management beginning in 1936, it converted to bus operation within that same year. The route extended service to Haymarket in April 1975 following the closure of the Charlestown Elevated, with partial extensions beyond Woodlawn introduced in January 2001. Service past Woodlawn was discontinued in September 2019; Cary Square short-turn trips were replaced by Woodlawn trips as of December 2021. The 111 ranks among the MBTA’s busiest 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 plans.

116/117

The 116 Wonderland Station–Maverick Station via Revere Street and 117 Wonderland Station–Maverick Station via Beach Street routes provided service to East Boston, Chelsea, and Revere. While both routes overlapped extensively through East Boston and Revere, their paths diverged primarily near Wonderland. According to the network plans released in May and November 2022, route 117 was set to be discontinued. The portion between Broadway and Wonderland Station was incorporated into an expanded route with increased frequency on this crucial corridor. This modification was implemented on December 15, 2024.

See also

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

External links

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