Key bus routes of the Massachusetts Bay Transportation Authority (MBTA) system are 15 routes that have high ridership and higher frequency standards than other bus lines, according to the 2004 MBTA Service Policy. Together, they account for roughly 40% of the MBTA's total bus ridership. These key bus routes ensure basic geographic coverage with frequent service in the densest areas of Boston, and connect to other MBTA services to give access to other areas throughout the region.
Route 1, which runs on Massachusetts Avenue, is one of the busiest MBTA bus routes, with service every 8 minutes during rush hour
A route 15 bus arriving at Nubian station in 2024
A route 28 bus at Nubian station in 2024 with its headsign advertising the fare-free program
Route 39 bus on Centre Street in 2017
The Silver Line is a system of bus routes in Boston and Chelsea, Massachusetts, operated by the Massachusetts Bay Transportation Authority (MBTA). It is operated as part of the MBTA bus system, but branded as bus rapid transit (BRT) as part of the MBTA subway system. Six routes are operated as part of two disconnected corridors. As of 2019, weekday ridership on the Silver Line was 39,000.
A Silver Line bus at South Station in 2023
The power changeover at Silver Line Way
An SL1 bus at Logan Airport Terminal E
An SL2 bus on Black Falcon Avenue
