THE MASSACHUSETTS DEPARTMENT of Transportation and the MBTA say an internal analysis by the two agencies recommends extending the Silver Line 3 bus to intersect with the Orange Line at Sullivan Square, a project that would cost an estimated $95 million and increase daily ridership by 15,000.

The SL3 currently starts at South Station and terminates at Chelsea station. The route started running in 2018 and makes stops in Seaport, East Boston, and Boston Logan International Airport. 

In 2021, MassDOT and the MBTA began working on a Silver Line extension analysis. The two agencies considered extending the Silver Line to Malden Center or to Wellington, which are both on the Orange Line. However, they settled on Sullivan Square as the station riders are most likely to choose but won’t move forward until funding is found. 

The report anticipates extending the SL3 bus to Sullivan Square would be achievable in a relatively short time frame because the existing SL3 fleet has the ability to serve the extension. Approximately 80 percent of the six-mile-long recommended extension would include exclusive bus-only lanes, with the SL3 serving eight new stations. T officials say, the implementation of the bus-only lanes for the SL3 will lead to faster times for pre-existing bus routes in the area that currently have to contend with traffic.

Chelsea, Everett, and Boston–all cities that will be impacted by this change–have endorsed the recommendation.

Everett Mayor Carlo DeMaria has previously called for the state to expand public transit options in his municipality, in part to accommodate fans going to see the Revolution play at a proposed soccer stadium near the Mystic River. The proposal for the 25,000-seat stadium has run into opposition on Beacon Hill but has the backing of Gov. Maura Healey.

Until the extension is completed, the MBTA will implement high frequency buses from Chelsea to the Orange Line to create rider demand for the new route.

The agency will also run buses from Sullivan Square to Kendall Square. The Silver Line extension analysis considered extending the SL3 beyond the Orange Line all the way into Kendall Square in Cambridge or to downtown Boston but determined that further study was required because that plan would require the MBTA to expand the Silver Line’s vehicle fleet and put resources toward additional maintenance facilities.