An extract on #instartist
The Commonwealth of Massachusetts was required under the Federal Clean Air Act to mitigate air pollution generated by the highway improvements. Secretary of Transportation Fred Salvucci signed an agreement with the Conservation Law Foundation in 1990 enumerating 14 specific projects the state agreed to build. This list was affirmed in a 1992 lawsuit settlement.
Projects which have been completed include:
Restoration of three Old Colony Commuter Rail lines
Extension of the Framingham Line to Worcester
Restoration of commuter rail service to Newburyport
Six-car trains on the MBTA Blue Line, requiring platform lengthening, station modernization, and all new train cars
MBTA Silver Line service to the South Boston waterfront
1,000 new commuter parking spaces
As of 2014, several mitigation projects were incomplete:
Green Line Extension to Somerville and Medford
Fairmount Line improvements
Design of the Red-Blue Connector at Charles Street (under petition to remove from list)
Some projects, such as restoration of Green Line "E" Arborway service, were removed from the list of mitigation projects and replaced with other projects with similar air-quality improvements.
In March 2011, it became known that senior MassDOT officials had failed to disclose an issue with the lighting fixtures in the O'Neill tunnel. In early February 2011, a maintenance crew found a fixture lying in the middle travel lane in the northbound tunnel. Assuming it to be simple road debris, the maintenance team picked it up and brought it back to its home facility. The next day, a supervisor passing through the yard realized that the 120 lb (54 kg) fixture was not road debris but was in fact one of the fixtures used to light the tunnel itself. Further investigation revealed that the fixture's mounting apparatus had failed, due to galvanic corrosion of incompatible metals, caused by having aluminum in direct contact with stainless steel, in the presence of salt water. The electrochemical potential difference between stainless steel and aluminum is in the range of 0.5 to 1.0V, depending on the exact alloys involved, and can cause considerable corrosion within months under unfavorable conditions.
After the discovery of the reason why the fixture had failed, a comprehensive inspection of the other fixtures in the tunnel revealed that numerous other fixtures were also in the same state of deterioration. Some of the worst fixtures were temporarily shored up with plastic ties. Moving forward with temporary repairs, members of the MassDOT administration team decided not to let the news of the systemic failure and repair of the fixtures be released to the public or to Governor Deval Patrick's administration.
As of April 2012, it appeared that all of the 25,000 light fixtures would have to be replaced, at an estimated cost of $54 million. The replacement work is mostly done at night, and requires lane closures or occasional closing of the entire tunnel for safety, and was estimated to take up to 2 years to complete. As of April 2016, replacement of the light fixtures is still ongoing.