MBTA crosstown bus routes

The Massachusetts Bay Transportation Authority (MBTA) operates two specially designated crosstown bus routes in the Boston, Massachusetts, United States area, called CT2 and CT3, and intended as limited-stop buses connecting major points. The two weekday-only routes largely parallel MBTA bus local routes, but with fewer stops to reduce travel times.

Three crosstown routes – CT1, CT2, and CT3 – were introduced in 1994. Eight additional routes numbered CT4 through CT11 were proposed as part of an interim phase of the Urban Ring Project to provide circumferential service bypassing the crowded downtown subway stations, but were never put in service. Route CT1 was merged with route in 2019. The Crosstown Routes will be phased out by 2028, according to current MBTA bus network redesign plans.

CT1
The CT1 Central Square, Cambridge–B.U. Medical Center/Boston Medical Center via M.I.T. (internally coded 701) ran between Central Square in Cambridge and the B.U. Medical Center/Boston Medical Center, mostly along Massachusetts Avenue. The majority of its route was a limited-stop version of route. Transfers to the 1 were possible at most of the stops. CT1 service was not substantially modified since its 1994 inception. Route CT1 was merged into route 1 in September 2019 to provide more frequent service and more consistent headways.

CT2
The CT2 Sullivan Square station–Ruggles station (internally coded 747) connects Sullivan Square in Charlestown with Ruggles in Roxbury via Kendall Square in Cambridge. The southern part of the route roughly parallels the. The route was created as a Ruggles–Kendall route in September 1994. In September 2000, the route was extended to Sullivan via Union Square.

, the route has 25-minute headways on weekday morning peaks, 40-minute headways on weekday afternoon peaks, and 60-minute headways middays. It does not have evening or weekend service. In May 2022, the MBTA released a draft plan for a systemwide network redesign. The draft called for route CT2 to be discontinued. Portions of the route would be covered by extensions of routes and  with higher frequency. A revised proposal in November 2022 again called for route CT2 to be discontinued, though the route 39 extension would be replaced with a more frequent route 47.

CT3
The CT3 Beth Israel Deaconess Hospital–Andrew Station (internally coded 708) connects the Longwood Medical Area to Andrew Square and runs entirely within the city of Boston. The route roughly parallels the. The stops at Avenue Louis, Pasteur, Children's Hospital, and Beth Israel Hospital are on a one-way loop.

The CT3 route started as Beth Israel–Andrew, but it was extended to Logan Airport in December 1998. The extension (internally coded 709) was dropped due to low ridership in March 2002. A few early morning trips were kept as the, running from Dudley to Logan. In January 2005, some rush hour service was rerouted to serve Newmarket Square.

, the route has 20–22 minute headways at peak hours, 30-minute headways in the early afternoon, and 80-minute headways midday. It does not have evening or weekend service. The May 2022 draft network plan called for route CT3 to be discontinued. It would be largely replaced by a new Brookline Village–Courthouse route running via Huntington Avenue, Ruggles station, Andrew station, and D Street. The November 2022 revised plan rerouted the replacement route via Brookline Avenue, Roxbury Crossing station, and Nubian station.