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About the Allston Multimodal Project

The Allston Viaduct, which carries the Massachusetts Turnpike (I-90) from the Allston Interchange to the Commonwealth Avenue Bridge, is nearing the end of its useful lifespan, and must be replaced.

Table of Contents

Project background

The Allston Interchange carries the Massachusetts Turnpike (I-90) through the Allston/Brighton area with Cambridge Street and Soldiers Field Road to the north and Brighton Avenue to the south. This is the primary east-west route between Western Massachusetts, Worcester, and Boston. It carries heavy vacation traffic during the weekends in the summer and winter.

Average daily traffic volumes for the Turnpike:

  • east of the Allston interchange are 147,000 vehicles per day (VPD)
  • Cambridge Street carries 38,000 VPD
  • Soldiers Field Road carries 66,000 VPD
  • the Allston Interchange Ramps carry 66,000 VPD

The need to replace the Allston Viaduct, and the change to All Electronic Tolling eliminating the need for toll booths in the interchange, give us the opportunity to straighten the Turnpike in Allston and make improvements to multimodal connections.

Since the spring of 2014, MassDOT and its Design Team have been developing a concept for the replacement of the Allston Interchange. We are working with a Task Force composed of:

  • local residents
  • advocates
  • elected and appointed officials
  • representatives of local institutions
  • businesses
  • the Allston community at-large

Additional Resources


  • southern limit - former CSX Beacon Park Rail Yard, north of the Boston University Athletic Center
  • northern limit - area of the I-90 Allston interchange ramps
  • eastern limit - Boston University Bridge/Commonwealth Avenue
  • western limit - Cambridge Street Bridge over I-90/Franklin Street footbridge
A map of the Boston area with the project area highlighted, and the Worcester/Framingham Commuter Rail Line labeled.


  • 2014 - current concept defined in the Environmental Notification Form (ENF) submitted to the Executive Office of Energy and Environmental Affairs (EEA)
  • November 2017 - MassDOT submitted the Draft Environmental Impact Report (DEIR), identifying a preferred concept for the new interchange design
  • February 2018 - EEA issued MassDOT a scope of work for a Final Environmental Impact Report (FEIR)
  • Summer 2018 - an Independent Review Team (IRT) analyzed options for the section of the project containing the Allston Viaduct, known as "the throat"
  • January 2019 - Secretary of Transportation selected the Soldiers’ Field Road (SFR) Hybrid for further analysis in the throat.  This concept would lower I-90 while raising Soldiers’ Field Road onto its own small viaduct
  • Summer 2019 - Project team conducted public outreach to MetroWest Communities, Boating Communities and Task Force to review construction impacts of the Soldiers Field Road Hybrid option.
  • October 2019 - Federal Highway Administration (FHWA) publishes Notice of Intent to prepare an Environmental Impact Statement in the Federal Register. This officially starts the federal National Environmental Policy Act (NEPA) environmental review of the project, to be processed as One Federal Decision (OFD) per Executive Order 13807
  • November 2019 - the NEPA Scoping Report was published. The Scoping Report updated the design of the 3K interchange alternative, re-named the 3L Re-alignment alternative, and presented three throat area options: the Highway Viaduct, At-Grade and SFR Hybrid designs. A 37-day comment period followed. It closed on December 12 and collected over 2000 individual substantive comments
  • August 2020 - the NEPA Scoping Summary Report was filed. The Scoping Summary Report updated the design of the highway viaduct and at-grade throat area options – re-named the Modified Highway Viaduct and Modified At-Grade, respectively, and identified three throat area design options under the 3L Re-alignment alternative would be moving forward to the DEIS for further analysis.
  • October 2020 - MassDOT held an additional round of public engagement as MassDOT formally requested the substitution of a Modified At-Grade option in place of the at-grade throat option presented in the Scoping Summary Report, one based on extensive discussions with the City of Boston.
  • November 2020 - Secretary Pollock announced the identification of a preferred throat option will happen after the next round of environmental filings and the No Build Major Preservation Alternative remains to allow time to build consensus on the throat area option and determine a finance plan for the project. Construction of the No Build option would also allow MassDOT to get through a lengthy permitting process should MassDOT pursue a build alternative at a later date.  
  • Winter 2020-Spring 2021- MassDOT and its Design Team are working to file a Notice of Project Change (NPC) to bring the State and Federal processes into alignment. The project team is also working towards filing a Supplemental Draft Environmental Impact Report (SDEIR) under the state MEPA environmental review process and the corresponding federal NEPA Draft Environmental Impact Statement (DEIS).

Project timeline

  • Concept development-through end of 2021
  • Public outreach-ongoing throughout project duration
  • MEPA/NEPA/Permit filings- First quarter 2021- through second quarter 2022
  • Preliminary Design- all of 2022-
  • Design-Build procurement- Fourth quarter 2022 through third quarter-2023 
  • Construction- Fourth quarter 2023-early 2024 - construction begins, lasting 6 to 10 years depending on the throat option selected
A timeline of the project from concept development to the end of construction. It is currently anticipated that construction will begin in 2022 and continue for eight to 10 years.

Project Benefits

The improvements made to I-90 as part of this project will allow the interchange to continue working as a crucial part of the Commonwealth's roadway network.

Improvements include:

  • Improved livability, connectivity, and open space for residents of the Allston neighborhood.
  • Improved regional mobility and roadway safety with the straightening of I-90. The project will also shrink the Allston interchange.
  • Replacing the aging Allston Viaduct, decreasing the need for traffic-impacting maintenance on this section of I-90
  • Creating a new open space along the Charles River
  • Complete Streets improvements to Cambridge Street
  • Enhanced bicycle and pedestrian connections
  • Significant transit enhancements with the new West Station and Commuter Rail layover facility, providing greater access and improvements to the commuter rail and local bus service.

Environmental Documentation Preview

In January 2019, the Secretary of Transportation selected the Soldiers’ Field Road Hybrid as the preferred concept for the throat area of the project. This concept would place Soldiers’ Field Road on its own small viaduct. I-90 would remain at ground level. Throughout 2019, the project team and Task Force worked to refine this concept. The NEPA Scoping Report, published in November 2019, suggested the SFR Hybrid to be carried forward to the DEIS for further analysis and suggested other designs for the throat area should be dismissed from further analysis.  The report detailed proposed construction methods associated with the SFR Hybrid throat area option. Construction of the SFR Hybrid would result in a single track of the Commuter Rail through the project area for a portion of construction duration. This option would also need to position Soldiers’ Field Road and the Dr. Paul Dudley White path on a temporary trestle in the Charles River to maintain traffic for much of the duration of construction, estimated to be between 8-10 years.

The public had 37 days to comment on the NEPA Scoping Report. The project received over 2000 individual substantive comments.  Public comment strongly opposed river and commuter rail impacts. A Scoping Summary Report was prepared in August 2020. It summarized and responded to comments received during the public comment period. From this feedback, the project team did the following:

  • Determined the No Build Alternative and the 3L Re-alignment Alternative would be carried for further analysis in the DEIS;
  • Determined that additional design options in the throat area would be analyzed in the DEIS to provide a comprehensive evaluation of impacts associated with three throat area options: the SFR Hybrid, Modified At-Grade and Modified Highway Viaduct;
  • Updated design of the at-grade option and highway viaduct option – re-named the Modified At-Grade and Modified Highway Viaduct, respectively
    • Providing for conditions which do not preclude at a later date, north-south pedestrian and bicycle connections in the At-Grade and Highway Viaduct Throat alternatives
    • Address visual impacts of the Highway Viaduct with aesthetic treatments;
  • Clarified the No Build Alternative. A No Build alternative, as required under NEPA, will also be analyzed in the DEIS. Reconstruction of the existing viaduct with a major preservation as a No Build Alternative to be implemented if the full multimodal project does not proceed;
  • Addressed major concerns about construction length and complexity and Charles River impacts; and
  • Determined an updated Modified Flip West Station option would be carried forward to the DEIS for further analysis. This updated design refined the rail design to include 4 tracks and 3 platforms at West Station.



Dan Fielding, Legislative Liaison - MassDOT Highway Division (857) 368-8959


Email the Project Team


Patricia Leavenworth, PE, MassDOT, Chief Engineer
10 Park Plaza
Attn: Bridge Project Management – Project File No. 606475
Boston, MA 02110