About the Somerville I-93 Viaduct preservation

This project will rehabilitate the I-93 Viaduct in Somerville between Exit 21 and Temple Street.

Table of Contents

Project details

Massachusetts Department of Transportation (MassDOT) will rehabilitate the I-93 Viaduct in Somerville between Exit 21 and Temple Street starting in Summer 2022. Work will take place from the Summer of 2022 to the Fall of 2025 to make necessary repairs and improvements to extend the life span of the Viaduct. Preservation work will consist of, but not be limited to:

  • Substructure concrete repairs
  • Structural steel repairs
  • Structural steel cleaning and painting
  • Bridge joint replacements
  • Concrete deck repairs
  • Associated traffic management

The work will impact local and regional roadway users. Return to this website to stay up to date on temporary detours, traffic changes, and construction schedules.

Aerial view of project site, showing roadways, landmarks and boundaries.

How will my commute and travel be affected?

Those traveling on I-93 in Somerville will be impacted by the rehabilitation work. During construction, I-93 travelers should expect:

  • Occasional overnight lane closures
  • Overnight ramp closures with detours

Those traveling on local roads in the vicinity of the viaduct will also be impacted by the rehabilitation work. During construction, local road travelers should expect:

  • Occasional daytime and nighttime lane closures
  • Occasional daytime and nighttime detours

These lane closures and detours will exclude holidays unless approved by MassDOT.

Work Hours

Work hours will vary between night work and day work, Sunday night through Friday, depending on construction activity. Generally, the daytime work hours will be 7:00 AM – 5:00 PM and the nighttime work hours will be 9:00 PM– 5:00 AM in accordance with the Contract requirements. Other workdays and times may be required. Prior to construction activity, notification will be sent out via email and information will be available on the project website.

Detour details

In coordination with local agencies and emergency services, the following detours were determined as the most efficient options during construction. Detours will be updated as construction progresses.

Route 28 Underpass to I-93 Southbound Detour

Route 28 Underpass to I-93 Southbound Detour map

There will be periodic nighttime closures of Route 28 Fellsway (McGrath Highway) Southbound underpass to I-93 Southbound and Route 38 Mystic Avenue Southbound between Middlesex Avenue and Garfield Avenue. Drivers will be detoured by continuing straight on Route 28 Fellsway (McGrath Highway) South under the Viaduct to the next left turn onto Route 38 Mysitc Avenue Southbound to the I-93 Southbound on-ramp. This detour will be used periodically overnight in 2024 and 2025.


Mystic Avenue Northbound Underpass Detour

Drivers will be rerouted from Route 38 Mystic Avenue northbound onto Middlesex Avenue and then be guided by signed detour onto Route 28/Fellsway. Rather than using the Mystic Avenue northbound underpass, drivers will travel under I-93 on Route 28/Fellsway and make a right turn onto Mystic Avenue northbound. This detour will be used periodically in 2022, 2023, and 2024.

Detour Map (PDF)

Drivers will be rerouted from Route 38 Mystic Avenue northbound onto Middlesex Avenue and then be guided by signed detour onto Route 28/Fellsway. Rather than using the Mystic Avenue northbound underpass, drivers will travel under I-93 on Route 28/Fellsway and make a right turn onto Mystic Avenue northbound. This detour will be used periodically in 2022, 2023, 2024, and 2025.


MBTA Route 95 Bus Stop Relocation

An aerial graphic showing the project location. The detour is depicted by an arrow going up Kensington Avenue and onto Middlesex Avenue. The key reads, “Relocated bus stop MBTA Route 95 (Mystic Ave opposite Kensington Ave), Pedestrian Route, and Relocated Bus Stop and Pedestrian Route Subject to Change.

Detour Map (PDF)

The MBTA Route 95 bus stop at Mystic Avenue Opposite Kensington Avenue will be temporarily relocated to Middlesex Avenue at Foley Street. The Bus Stop will be relocated periodically in 2022, 2023, 2024, and 2025.


Temple Road (South and North) Detours

Temple Road Detour South map
Temple Road Detour North map

Detour Map - South (PDF) 
Detour Map - North (PDF)

These detours will be used periodically in 2023, 2024, and 2025.


Route 28 Westbound Underpass Detour

An aerial graphic showing the project location. The detour is depicted by an arrow going up Mystic Avenue, taking a left on the Fellsway, and then taking a right back onto Mystic Avenue. The key says “nightwork subject to change”.

Detour Map (PDF)

While the I-93 underpass is closed, traffic will be guided by signed detour around the underpass via Mystic Avenue. This detour will be used periodically in 2023, 2024, and 2025.


I-93 Northbound On-Ramp Detour

An aerial graphic showing the project location. The detour is depicted by an arrow going up I-93 and onto Mystic Avenue. The key reads, “night work subject to change.” Above the detour is a call out for the Assembly Square Marketplace, below is one for Foss Park, and to the right is one for Stop & Shop.

Detour Map (PDF)

Access to the I-93 northbound on-ramp at Mystic/Fellsway will be shifted to the on-ramp located near Moreland Street. This detour will be used periodically in 2023, 2024, and 2025.


I-93 Southbound Off-Ramp Detour

I-93 Southbound Off-Ramp Detour map

Access to the I-93 southbound off-ramp will be shifted from Exit 20 to Exit 21. This detour will be used periodically in 2023, 2024, and 2025.


Route 28 Eastbound Connection to I-93 Southbound Detour

An aerial graphic showing the project location. The detour is depicted by an arrow going down Route 28 and onto I-93. The key says, “Nightwork subject to change” Above the detour is a call out for the Assembly Square Marketplace, below is one for Foss Park, and to the right is one for Stop & Shop.

Detour Map (PDF)

The Route 28 eastbound connection to the I-93 southbound on-ramp at Exit 20 will be shifted to the Route 28 westbound connection. This detour will be used periodically in 2023, 2024, and 2025.


I-93 Northbound Off-Ramp Detour

An aerial graphic showing the project location. The detour is depicted by an arrow going up I-93, doing a U-turn at the traffic circle, taking a left onto Middlesex Avenue, and then a right onto Route 28. The key says, “No earlier than 12 a.m. and open by 5 a.m.” Above the detour is a call out for the Assembly Square Marketplace, below is one for Foss Park, and to the right is one for Stop & Shop.

Detour Map (PDF)

Access to the I-93 northbound off-ramp will be shifted from Exit 21 to Exit 23. This detour will be used periodically in 2023, 2024, 2025.


Mystic Ave Northbound U-turn Detour

Mystic Ave Northbound U-turn Detour map

The U-turn from Mystic Avenue northbound to I-93/Mystic Avenue Southbound will be restricted. Traffic will be guided by signed detour past the U-turn and back onto Mystic Avenue. This detour will be used periodically in 2023, 2024, and 2025.


Mystic Ave Northbound and Northbound On-Ramp Detour

An aerial graphic showing the Mystic Ave on-ramp detour.   The northbound detour includes day and night work.  The northbound on-ramp and the northbound detours are for night work.

Detour Map (PDF)

Northbound traffic on Mystic Avenue will be guided by signed detour onto Middlesex Avenue, around the viaduct, and back onto Mystic Avenue. From there they will be directed onto I-93 northbound on-ramp. Southbound traffic on Middlesex Avenue will be guided by a signed detour onto Foley Street and back to Mystic Avenue northbound. This detour will be used periodically in 2023, 2024, and 2025.

How will my neighborhood be affected?

Learn more about neighborhood impacts and traffic disruptions along with our plans to reduce their effects on you.

Overhead view of the impacted neighborhood with major roadways  and landmarks pointed out.

What to expect

We understand that some communities will be more heavily impacted by the restoration efforts than others. Aside from the effects on travelers and commuters, we understand that Somerville residents will see more traffic and noise in their communities during construction. We are committed to finding ways to minimize the effects of construction and reduce their impacts across the board. 

Ten Hills, Winter Hill, and Assembly Row residents and business owners

We understand that Ten Hills, Winter Hill, and Assembly Row residents and business owners may see more traffic in their neighborhoods as drivers detour through the local roads of Somerville.

Here is our plan to help minimize some of these effects:

  • The detour will be clearly marked on signs throughout the route.
  • Noise should be expected during construction. Noise monitoring may be required to track compliance within allowable limits. Noise suppression devices such as enclosures and barriers may be used, if required.
  • If required, the project team will utilize pesticide technologies such as trapping and monitoring devices to control pests within the project limits.
  • The construction team is required to use OSHA best practices to control the dust.
  • An email address has been created to allow the public to submit questions, comments, and concerns. Please reach out to us at MassDOTi93SomervilleViaduct@dot.state.ma.us

Public involvement opportunities

Stay informed

Sign up for construction updates, email alerts, and the latest information on the I-93 Somerville Viaduct Preservation project to help you make informed travel decisions.

Project email address: MassDOTI93SomervilleViaduct@dot.state.ma.us

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