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State Implementation Plan

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Project and Services

The State Implementation Plan (SIP) – as approved in regulation by both the Massachusetts Department of Environmental Protection and the U.S. Environmental Protection Agency – requires that MassDOT and the MBTA complete the following transportation improvement projects:

  • Green Line Extension to Medford Hillside,
  • Green Line Extension to Union Square (Somerville),
  • Upgrade of the MBTA Fairmount Commuter Rail Line, including the construction of four new stations: Four Corners (Dorchester) and one new station each in the Dorchester, Mattapan, and Roxbury neighborhoods, and
  • Construct 1,000 new parking spaces serving commuter transit facilities (complete).

Together, these projects are intended to reduce certain air pollutants in eastern Massachusetts. Questions about the SIP projects should be directed to the Office of Transportation Planning

SIP Transit Commitment Submissions
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