State officials announced the start of the next phase of a bike and pedestrian path along the Green Line Extension in Somerville and Cambridge.

The 1.9-mile path will connect four Green Line Extension stations: Lowell Street, Gilman Square, Washington Street and the relocated Lechmere.

MassDOT Secretary Richard Davey made the announcement Wednesday morning. Half of the $39 million cost will be paid by federal funding.

 The project will be completed in 2020, the same year the Green Line Extension is expected to start running, according to MassDOT. Somerville will be responsible for operation and maintenance of the path, which will include wireless alarm call boxes, lighting, landscaping and benches.

The original portion of the community path was constructed in the 1980s between Alewife Linear Park and Davis Square. The first extension to Cedar Street was completed in 2011. The next phase to Lowell Street is expected to be completed this fall.