66 (MBTA bus)

Massachusetts Bay Transportation Authority (MBTA) Primary Bus Routes
Company type	Public transit service
Industry	Public transportation
Founded	2004
Headquarters	Boston, United States
Area served	Boston metropolitan area
Products	Bus transit services

Adapted from the English Wikipedia article 66 (MBTA bus), available under CC BY-SA 4.0Updated 7 August 2025

Primary bus routes within the Massachusetts Bay Transportation Authority (MBTA) consisted of 15 high-demand corridors that adhered to more rigorous frequency benchmarks than other lines, according to the 2004 MBTA Service Policy. Collectively, these routes represented roughly 40% of the MBTA's total bus ridership. They played a critical role in serving Boston’s most densely populated neighborhoods and provided connections to other MBTA transit modes, enhancing regional mobility.

Designated as a fundamental component of the MBTA’s transit network, these primary bus routes appeared on updated system maps alongside rapid transit rail, bus rapid transit, and commuter rail lines. This classification facilitated focused service enhancements such as late-night service experiments and drew interest from urban planners and transportation engineers. With the introduction of the 2024 Bus Network Redesign, the designation "key bus route" is being phased out in favor of a more extensive high-frequency route framework.

History

In November 2006, the MBTA initiated programs aimed at elevating service quality on its primary bus corridors. The 2008 Service Plan advocated for improvements on several lines, including promoting route 31 to primary route status. A subsequent $10 million Key Routes Improvement Project was financed through the 2009 American Recovery and Reinvestment Act. Though initially encompassing Silver Line services—which were later separated administratively—the project concluded in 2013 with some enhancements left unfinished. Service dependability on these primary routes has consistently surpassed that of other lines, achieving a 75% on-time performance rate compared to 61% as recorded in June 2017.

Research conducted in 2012 indicated that proximity to primary bus corridors correlated with a decrease in taxi trip generation, suggesting these frequent-service routes effectively compete with taxi services for riders who have alternative travel choices.

In April 2014, extended late-night operations were launched on primary bus and rapid transit lines as a one-year pilot program contingent on ridership levels and sponsorship support. However, by April 2015, late-night hours were curtailed and eliminated on five key routes, with all late-night service discontinued by March 2016.

These primary bus routes were integral to Boston mayor Marty Walsh’s "Go Boston 2030" plan, which sought to ensure every residence was within a ten-minute walk of either a T station or a primary bus stop. A proposed new primary route aimed to link the Longwood Medical Area with JFK/UMass station through Roxbury.

In May 2022, the MBTA unveiled a draft Bus Network Redesign proposing modifications to most primary routes and elevating additional lines into a high-frequency network designed to complement rapid transit services. An updated version of this plan was issued in November 2022.

Criteria for Primary Routes

According to the MBTA's Service Delivery Policy, five factors determine designation as a Primary Bus Route:

Elevated ridership demand
Integration within the transit system
Broad geographic reach
Support for significant new development projects
Operation under bus rapid transit standards

Service Requirements

Primary routes are required to maintain superior service spans and frequencies compared to typical local routes.

Route Category	Minimum Service Span
Local	Weekday	7:00 AM – 6:30 PM
	Saturday	8:00 AM – 6:30 PM
	Sunday	10:00 AM – 6:30 PM
Primary	Weekday	6:00 AM – Midnight
	Saturday	6:00 AM – Midnight
	Sunday	7:00 AM – Midnight

Route Category	Minimum Frequency of Service
Local	AM & PM peak	Every 30 minutes
	Off-peak periods	Every 60 minutes
	Weekend days	Every 60 minutes
Primary	AM & PM peak	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 due to frequent requests from both officials and the public for express or limited-stop services aimed at enhancing operational efficiency and addressing high ridership demands.

1

The 1 Harvard Square–Nubian Station line connects Cambridge to Roxbury and was established in September 1962 by combining two separate routes that previously intersected at Massachusetts Avenue (currently Hynes Convention Center). In May 1987, the route was modified to divert from Washington Street southeastward along Albany Street and Melnea Cass Boulevard to provide access to Boston Medical Center. Its path largely traces Massachusetts Avenue, departing from Harvard station, passing the MIT campus, crossing the Charles River via the Harvard Bridge into Boston, continuing past Berklee College of Music to Boston Medical Center, then heading southwest to Nubian station through Albany Street and Melnea Cass Boulevard.

By 2015, Cambridge intended to implement signal priority at selected intersections for route 1. No alterations were suggested in the network plans released in May and November of 2022.

In October 2023, the transit advocacy organization Transitmatters identified the 1 bus as the slowest and most prone to bunching within the MBTA system—averaging a speed of just 6.55 mph and exhibiting a bunching rate of 17.7%, meaning roughly one in six buses experienced bunching.

15

The 15 Fields Corner Station or St. Peter's Square–Ruggles Station service operates from St. Peter's Square in northern Dorchester northward along Bowdoin Street, then west on Hancock Street and north via Columbia Street to Uphams Corner. It proceeds west along Dudley Street toward Nubian station, continues west on Malcolm X Boulevard, and then heads north on Tremont Street ending at Ruggles station. Evening and weekend trips terminate at Fields Corner station, traveling via Geneva Avenue and Bowdoin Street back to St. Peter's Square.

On April 6, 1962, buses replaced trackless trolleys on what was formerly the 15 Kane Square–Dudley route. Following the Orange Line’s relocation to the Southwest Corridor in May 1987, this route was extended to Ruggles. Service from Kane Square was slightly extended to St. Peter's Square as of August 25, 2024.

The draft network plan from May 2022 proposed extending this route westward to Oak Square, absorbing route , thereby creating an Oak Square–Fields Corner line. However, the November 2022 draft plan reverted this change by truncating it back to Ruggles and maintaining route 65 as a separate line.

22

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

This service replaced trackless trolleys on April 6, 1962; initially operating as route 22 Ashmont–Dudley via Talbot and Warren Streets with a northern extension along Warren Street reaching . When the Orange Line moved in May 1987, it was extended to Ruggles. The May and November 2022 network proposals included plans to shift the inner terminal to the 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, the bus heads north along Washington Street, then turns onto Warren Street toward Nubian station. From Nubian, it travels west on Malcolm X Boulevard to reach Roxbury Crossing, then continues north along Tremont Street until arriving at Ruggles station.

This route transitioned from trackless trolley service to buses on April 7, 1962, and was extended to Ruggles in May 1987 coinciding with the Orange Line relocation. A 2017 analysis highlighted overcrowding issues on routes 23 and 28, recommending an extension and increased frequency for route 29 as a remedy. Between March 1, 2022, and February 28, 2026, a city-funded fare-free initiative covers routes 23, 28, and 29. No modifications were suggested for route 23 in the network redesign proposals released in May or November 2022.

28

The 28 Mattapan Station–Ruggles Station line connects the Grove Hall and Mattapan neighborhoods via Blue Hill Avenue, a principal thoroughfare. Historically, Blue Hill Avenue functioned as a heavily trafficked trunk corridor; for example, in 1945, route 29 Mattapan–Egleston operated with headways as short as 1.5 minutes during morning peak periods. Streetcars previously ran on a dedicated right-of-way until buses replaced them in 1955. Established in May 1987 to supplement route 29 service, route 28 became the dominant service along Blue Hill Avenue by December 1989, while route 29 was limited to rush hour and shorter trips. Passenger shelters were installed at select stops in 2001. Between December 2006 and June 2010, a short-turn service designated as route 25 operated during morning rush hours.

The 2003 Program for Mass Transportation explored multiple Silver Line expansion options; notably, a bus rapid transit (BRT) overlay for route 28 reemerged in Silver Line Phase III plans around 2006. In 2009, state authorities proposed the 28X limited-stop BRT line—the busiest bus corridor in New England—featuring dedicated lanes and queue jump signals, with an estimated cost of $114 million and construction scheduled between 2010 and 2012.

Community opposition arose due to insufficient local engagement, concerns about parking loss, and potential traffic disruptions, leading the state to withdraw the plan by late 2009. In June 2010, the MBTA introduced articulated (60-foot) buses on route 28 to enhance capacity; this change prompted resident objections regarding proposed stop eliminations in Grove Hall. The subsequent Roxbury–Dorchester–Mattapan Transit Needs Study of 2012 recommended implementing the express bus service concept of the 28X without constructing new infrastructure.

In August 2020, MBTA and City of Boston officials applied for $15 million in federal funds toward a $30 million Blue Hill Avenue improvement project that includes center-running bus lanes, targeting completion by the end of 2021; however, the application was denied in September. A second federal funding request for $25 million was submitted in July 2021. From August 2021 through February 2022, a city-funded pilot program provided free fares and all-door boarding on this frequently delayed route to enhance reliability. Following this pilot, fare-free service on routes 23, 28, and 29 was extended through February 2026. In November 2021, Boston secured a $15 million federal grant supporting the Blue Hill Avenue reconstruction initiative.

The network redesign proposals released in May and November of 2022 suggested extending route 28 from Roxbury Crossing to via Longwood Medical Area while eliminating the segment between Roxbury Crossing and Ruggles. In February 2024, the city announced plans for a $44 million Blue Hill Avenue reconstruction project featuring center bus lanes, with construction anticipated 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. Throughout its entire course, it runs adjacent to the commuter rail tracks.

Prior to 1953, Route 32 functioned as a trolley service extending from Forest Hills to Cleary Square before transitioning to trackless trolley operation. By 1958, diesel buses replaced trackless trolleys on the segment south of Forest Hills. The trackless trolley turnaround loop 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 combined with Route 32 at Cleary Square, creating the Route 32 Forest Hills–Wolcott Square. Meanwhile, Route 50, which served Cleary Square and Forest Hills via Roslindale, was redirected to cover the Malone Elderly Housing area. No modifications were suggested in the network proposals released in May and November 2022.

39

The 39 Forest Hills Station–Back Bay Station route took over the Green Line E branch service from Heath Street to Arborway starting in December 1985; this change was initially labeled as "temporary" until 2011. It parallels the Green Line corridor from Heath Street to Copley and provides transfers to both the Orange Line and commuter rail at either terminus, with Amtrak connections available at Back Bay.

Route 39 was pioneering for the MBTA as its first route to consistently utilize articulated buses, a practice later adopted by other lines such as Route 28 in late 2005. By 2013, it ranked as Boston’s second busiest bus route. Its substantial ridership played a role in prompting the expansion of Forest Hills station during the Casey Arborway reconstruction.

The May 2022 draft network plan suggested extending Route 39 through and , replacing portions of routes , , and , while eliminating service between Longwood Avenue and Back Bay. However, the November 2022 plan restored Route 39 to its original path and instead proposed increasing frequency on Route 47 with an extension to Union Square.

57

The 57 Watertown Yard–Kenmore Station line connects Boston, Newton, and Watertown. It was introduced following the discontinuation of the Green Line A branch in 1969. Previously, Route 57 offered limited-stop service within Boston—avoiding pickups along Commonwealth Avenue between Packard's Corner and Kenmore Square—but this practice ended in December 2006. No alterations were proposed for this route in either the May or November 2022 network plans.

66

The 66 Harvard Square–Nubian Station via Allston route—originally operated as a trolley line—starts at Nubian Square in Roxbury and crosses the Southwest Corridor Park near Roxbury Crossing. It runs parallel to both Route 39 and the Green Line E branch between Brigham Circle and Boston’s city limits. Following Harvard Street, it serves Brookline and Allston neighborhoods, detours through Union Square, then continues along Cambridge Street and North Harvard Street before terminating at Harvard Square in Cambridge. This route offers connections to several transit lines: Silver Line at Nubian station; Orange Line at Roxbury Crossing; Green Line branches E, D, C, B; and Red Line at Harvard station. The May and November 2022 plans did not propose any changes for this route. In August 2024, northbound buses 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, then proceeds south onto Mount Auburn Street before turning westward into Watertown, concluding at Watertown Square. At Harvard, the bus completes its loop by traveling along Massachusetts Avenue, Garden Street, and Waterhouse Street before returning to the tunnel. In Watertown, a dedicated right-of-way loop allows for efficient turnaround and passenger boarding.

Streetcar operations on route 71 ceased on September 4, 1958, with trackless trolleys taking over until March 13, 2022. In 2017, routes 71 and 73 were chosen for a bus rapid transit pilot initiative. Alongside other routes, these represented some of Boston’s final trackless trolley lines before transitioning to diesel buses in 2022. The 2022 network redesign did not propose modifications to this route; however, Watertown intends to extend service slightly to Watertown Yard as part of reconfiguring Watertown Square.

73

The 73 Waverley Square–Harvard Station begins within the Harvard bus tunnel and shares its path with route 71 along Mount Auburn Street through Cambridge and Watertown. It then follows Belmont Street—which runs along the boundary between Belmont and Watertown—continues along Trapelo Road in Belmont, and terminates at Waverley Square. The route loops near the Waverley commuter rail station on the Fitchburg Line.

Originally operated by streetcars into the 1950s, route 73 introduced trackless trolleys in 1957 for short-turn trips and fully converted by 1958. Trackless trolley service persisted until March 13, 2022. Recent network proposals have not suggested any alterations to this route.

77

The 77 Arlington Heights–Harvard Station line connects Arlington with Harvard station via Massachusetts Avenue. Prior to the Red Line Northwest Extension in the 1980s, routes 77/77A served as the main transit option 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 switched to trolleybus operation in 1958 to free up streetcars for the Highland branch conversion and eliminate boarding islands that interfered with automobile traffic. Route 77A handled all local stops south of the carhouse while route 77 made limited stops in that area; from 1998 until 2005, route 77 largely replaced service provided by route 77A, which was ultimately discontinued in 2022. In 2017, Arlington pursued private funding for signal priority measures, queue jumps, and potential bus lanes along its segment. The May and November 2022 network plans did not propose any changes for this route.

111

The 111 Woodlawn–Haymarket Station connects downtown Boston to Chelsea via the Bill Russell Bridge and Tobin Bridge. Initially a streetcar line running between Chelsea Square and Woodlawn that was acquired by the Boston Elevated Railway in 1936, it was converted to bus service later that year. The line was extended to Haymarket in April 1975 following the closure of the Charlestown Elevated, with partial extensions beyond Woodlawn added 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 remains one of the MBTA's highest-frequency bus routes, operating every five minutes during peak hours. No proposed modifications were included for this line 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. These two lines followed largely overlapping paths through East Boston and Revere, with their primary difference occurring near Wonderland. According to the network proposals from May and November 2022, route 117 was set to be eliminated, with the portion between Broadway and Wonderland station incorporated into an extended route to preserve essential bus frequency. This adjustment was implemented on December 15, 2024.

External links

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