Accelerated Bridge Program Massachusetts Department of transporatation

Project Overview

Traffic Management

The Longfellow Bridge carries the MBTA Red Line and thousands of vehicles, pedestrians and bicyclists each day. Due to the compressed construction period and to protect the bridge’s users and construction workers, traffic will have to be shifted as work progresses.

The contractor is required to maintain emergency response, MBTA Red Line service, and bicycle and pedestrian access on the bridge at all times. During construction, one lane of traffic carries vehicles into Boston and Cambridge-bound traffic is being detoured using a signed route. Vehicles using the Cambridge-bound detour may use the First Street exit ramp to Main Street in Kendall Square. An alternate detour route uses the Massachusetts Avenue Bridge. Details on the detour routes and maps can be found on the Traffic Information page. Vehicles wishing to reach Boston from Land Boulevard should use Binney Street and Third Street to reach Main Street or stay on Memorial Drive westbound and use Wadsworth Street to Main Street. Please note: Memorial Drive has truck restrictions.

The project includes replacing the MBTA Red Line tracks, and other work in close proximity to them.
Learn more on the Red Line Weekend Diversion webpage.

To report issues or concerns or for questions related to construction, please use the dedicated project hotline, 617-519-9892, or the project email address,

About the Work

In this design, the bridge's distinctive architectural features will be preserved or restored, while the deteriorated structural elements of the bridge are carefully rehabilitated. All new elements of the work will be sensitively designed to complement the bridge's historic character and its prominent position within the historic Charles River basin.

The primary objective of the rehabilitation is to address the bridge's current structural deficiencies, upgrade its structural capacity, and bring the bridge up to modern code. In particular, the structural steel elements supporting the bridge deck have deteriorated and require upgrading, and the abutments will have to be modified slightly to allow the sidewalk approaches to meet Americans with Disabilities Act (ADA) accessibility guidelines. At the same time, the bridge's ornate pedestrian railings will be restored or replicated, its masonry elements will be cleaned and conserved, and an appropriate new bridge lighting system will be designed. Areas on the riverbanks disturbed by the project will be carefully landscaped to tie the bridge into its historic setting.

Updated renderings of the completed bridge rehabilitation project are available for review.


The Longfellow (originally, the Cambridge) Bridge is one of the most architecturally distinguished bridges in Massachusetts. Located on the site of the 1793 West Boston Bridge, this graceful steel and granite structure was completed in 1908, and renamed to honor Henry Wadsworth Longfellow in 1927. The bridge joins Cambridge Street in Boston with Main Street in Cambridge and carries the Massachusetts Bay Transportation Authority (MBTA) Red Line and two-way vehicular traffic across the Charles River. The bridge presently carries 28,000 motor vehicles, 90,000 transit users, and significant numbers of pedestrians and bicyclists each day.

The 1908 bridge was extended in 1956 and rehabilitated in 1959. The bridge today consists of eleven original open-spandrel steel arch spans plus two steel girder approach spans at the Cambridge end. The bridge has an overall length of 2,135 feet, and a deck width of 105 feet, which includes a 27-foot fenced median occupied by the Red Line. The existing cross-section provides an upstream 6-foot sidewalk and a 33-foot wide roadway while the downstream side consists of a 10-foot sidewalk and 29-foot wide roadway. The bridge's substructure is built of granite block masonry and consists of ten hollow piers and two hollow abutments. The two central piers carry the signature pairs of neoclassically inspired dressed granite towers that have given the bridge its popular nickname - the Salt and Pepper Bridge.

Environmental and Historic Resources
The project team will continue to review key historical, architectural and environmental aspects of the rehabilitation, including coordinating with Section 106 Consulting Parties (Massachusetts Historical Commission, Boston Landmarks Commission and Cambridge Historical Commission), the Boston and Cambridge Conservation Commissions and the Massachusetts Department of Environmental Protection (MassDEP). A landscape architect and a certified arborist are part of the project team.
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