MassDOT has engaged a design-build team for the superstructure replacement of the Commonwealth Avenue Bridge, over Interstate 90 (I-90) and the MBTA commuter railroad in Boston. As a key member of the project’s design-build team, McMahon is responsible for preparation of the temporary traffic control, traffic signal, and lighting plans, for the planned August 2017 and August 2018 replacement of the bridge structure.
McMahon is coordinating with the project team to design effective temporary traffic control plans that will allow the contractor to replace the bridge, in the most cost- and time-effective manner. Traffic control for this project involves the full closure of Commonwealth Avenue and shut-down of the Green Line for approximately two weeks and closures on the I‑90 for 10 days. McMahon is developing plans to manage pedestrians, bicycles and vehicles, including MBTA and other shuttle buses, affected by the closures. Plans include complicated construction detours, including creation of separate lanes for buses only through the work area, crossovers on I‑90, and an extensive real-time traffic management system. Final design includes enhanced bicycle and pedestrian accommodations, supplemented with innovative solutions such as floating bus islands.
We participated in numerous meetings with MassDOT, MBTA, the cities of Boston and Cambridge, Boston University, emergency responders, and many other stakeholders, to review designs and discuss potential construction traffic management alternatives. McMahon also oversaw MBTA and Boston University buses “test run” through the proposed contra-flow detour route, which was performed during overnight hours, to avoid transit service disruption. This test run enabled us to field verify the proposed set up, and ensure that bus operators would be comfortable with the unusual turns and narrower travel lanes.