Massachusetts Bay Transportation Authority (MBTA) Massachusetts Department of Transportation
Green Line Extension Green Line Extension


The Green Line Extension is a top transportation priority of the Commonwealth. It offers a number of benefits:

  • A one-seat ride from the project corridor to downtown Boston, (eliminating the need for bus and rail transfers at Lechmere Station and at Orange and Red Line stations) improving travel times within the project corridor.
  • A projected reduction in regional daily Vehicle Miles Traveled by 25,728 miles, improving air quality and reducing automobile congestion.
  • Daily ridership (boardings and alightings) at the seven Green Line Extension stations of approximately 45,000 by 2030. The majority of those trips will be made beginning in the first year of service on the Green Line Extension.
  • A commitment to universal access, with new stations that will meet or exceed the Americans with Disabilities Act (ADA) standards.
  • Operation in existing railroad rights-of-way, reducing the need to purchase local property and minimizing construction impacts.
  • Mitigation measures that will reduce existing noise and vibration impacts from area railroads.

Additional Project Overview Details

Notice of Project Change on Extension of the Green Line to Mystic Valley Parkway

This Notice of Project Change (NPC) discusses a potential one-mile extension of the Green Line from its currently proposed terminus at College Avenue in Medford to Mystic Valley Parkway (Route 16) in Medford and Somerville. The extension of the Green Line will be along the existing MBTA Lowell Line commuter rail right of way. The 2009 Draft Environmental Impact Report (DEIR) evaluated and identified the extension to Mystic Valley Parkway as part of the Preferred Alternative; however, due to fiscal constraints, MassDOT deferred this extension to a future phase.

At the request of the cities of Medford and Somerville, as well as the Boston Metropolitan Planning Organization (MPO), MassDOT agreed to move forward on this initial step of the environmental review process by filing this NPC. While no funding source or timeline for project construction has been established yet, the Mayors of Medford and Somerville and other elected officials urged MassDOT to begin this process while the GLX project to College Avenue is underway so that the project will be advanced and well positioned should funding become available.

Given the significant amount of time since that prior environmental review, and in light of the many changes to the neighborhoods along the corridor since 2009, MassDOT and the MBTA believe that a new environmental review, in which the community and stakeholders have ample opportunity to participate, is warranted.

The purpose of this NPC is to initiate additional state environmental review for the extension to Mystic Valley Parkway, as well as provide an opportunity for public input on proposed station design concepts for Mystic Valley Parkway Station. The MBTA anticipates that this environmental review will address all of the impacts of the project (e.g., traffic, noise, vibration, historic impacts, etc.) as well as construction period impacts. The environmental review will also analyze and estimate benefits of the project, such as reduced automobile traffic, associated air quality benefits, land use and water quality benefits, as well as other positive results from the project. This analysis will be performed and presented in both a Draft and Final Environmental Impact Report which will be prepared for the project after this preliminary step in the environmental review process is completed.

EEA will now accept public comments on this document. See the flyer for information about the NPC Public Meeting and how to comment. Comments must be submitted to the EEA by 5:00 PM on December 12, 2017.

Copies of the environmental document have also been placed at the following local libraries:

Contract Status

Status of Construction and Management/Design Contracts.

More about Contract Status

FTA Participation

Information about the project's Federal Transit Administration (FTA) New Starts Full Funding Grant Agreement (FFGA).

More about FTA Participation

Environmental Approvals

National Environmental Policy Act (NEPA) & Massachusetts Environmental Policy Act (MEPA) details.

More about Environmental Approvals

Proposed Project Schedule

The GLX project will now be proceeding under the Design Build procurement method.

More about the Proposed Project Schedule

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