The project, as proposed by MassDOT, is located within the Allston neighborhood of the City of Boston and includes the area encompassed by the former Beacon Park Yards (BPY) railyard. The project area is bounded by Ashford Street to the south, the Commonwealth Avenue Bridge and the Charles River to the east, Cambridge Street to the north, and Cambridge Street and the Franklin Street pedestrian bridge over I-90 to the west.
Within the project area, the existing I-90 interchange dates from the original construction of the Boston Extension of I-90 in the 1960s. Today, I-90 carries four travel lanes in the eastbound direction and four travel lanes in the westbound direction outside of the interchange or ramp terminals, portions of which are located on a viaduct. Within the interchange (between ramp terminals), the number of lanes in each direction decreases to three, and carries over 140,000 vehicles per day, serving as a significant part of the regional and local infrastructure and connecting Logan Airport, I-93 and downtown Boston with areas to the west with connections to I-95 and I-495. I-90 westbound traffic currently passes between the I-90 eastbound exit bridge piers, located just west of the former I-90 toll plaza that was removed in early 2017. The conditions in the interchange, like much of the Boston Extension, do not meet current interstate highway design standards, especially as the interchange geometry was originally designed to accommodate a traditional toll plaza and to avoid segmenting the BPY railyard.
The project area also includes Soldiers Field Road (SFR), a parkway, and the adjacent Paul Dudley White (PDW) Path, a shared-use path along the banks of the Charles River. Both SFR and the PDW Path are part of the Charles River Reservation under the care, custody and control of the Massachusetts Department of Conservation and Recreation (DCR), and within the bounds of the Charles River Basin Historic District, which is listed in the National Register of Historic Places. SFR is a major crosstown street and is an important element of regional transportation within the area. SFR also has a 10’ height limit, restricting most commercial and oversized vehicles from using the parkway. Most of the remainder of the land within the project area is presently owned by Harvard University, with the existing I-90 interchange and railroad facilities operated by MassDOT via land easements.
In addition to I-90, SFR, and the PDW Path, the Worcester Main Line tracks and Grand Junction Railroad (GJR) run though the Project Area, which serve as critical infrastructure for Amtrak and the Massachusetts Bay Transportation Authority (MBTA) commuter rail operations. The two-track Worcester Main Line runs through the southern part of the project area. From west to east, the Worcester Main Line is located south of I-90, passes under the Cambridge Street Bridge, continues straight between the rail yard and develop In aded land to the south, and curves south to continue underneath the I-90 viaduct at the eastern extent of the project area. The Worcester Main Line serves MBTA commuter rail, Amtrak, and CSXT Freight Service. The Boston to Springfield rail line is also used by Amtrak intercity rail passenger service and was designated by Congress as a High-Speed Intercity Rail Corridor. Additionally, the GJR line runs beneath the I-90 viaduct, over SFR on a two- span bridge, and over the Charles River on a multi-span bridge that passes beneath the Boston University Bridge.
Proposed improvements are needed within the project area due to existing roadway deficiencies which include a structurally deficient viaduct on the I-90 mainline and substandard geometric elements on both the mainline and within the interchange; existing safety deficiencies which include substantially higher than average crash rates for the mainline and the interchange; existing mobility deficiencies which include a deficient level-of-service within the interchange, commuter rail limitations, lack of multimodal connections, and inadequate bicycle and pedestrian facilities; and limited multimodal access to the Charles River Reservation. The purpose of the project is to address roadway deficiencies, address safety issues, improve mobility of I-90 mainline and I-90 interchange 18, 19, and 20 in Allston, and improve multimodal transportation access to and within the Charles River Reservation.