3 | Brookline

This segment presents several major challenges, both technical and political. Technically, it includes two of the project’s most expensive infrastructure investments (the Charles River crossing and the proposed Fenway-Ruggles Tunnel). This segment must integrate with existing systems, including three branches of the Green Line and the Framingham/Worcester commuter rail line, and it must contend with the complex geometry of the Charles River crossing. Politically, it knits together three separate municipalities and several major institutional stakeholders, all of which have their own priorities.

At the same time, successfully implementing this segment offers some of the greatest benefits for the overall project. The connection with commuter rail offers riders the opportunity to circumvent downtown Boston. Connecting centers of employment on opposite sides of the Charles River (Kendall Square in Cambridge and the Longwood Medical Area in Boston) presents promising opportunities for regional economic development.

BU Bridge

BU Bridge


The existing multimodal transportation system in Segment 3 includes several radial transit and automobile routes extending from Downtown Boston to communities to the west. The segment is relatively well-served by transit with the Green Line Branches B, C, and D as well as commuter rail service at Yawkey Station and multiple bus routes. The main transportation challenges in this section are the fact that there are few continuous north/south connections that cross existing barriers such as the Charles River, Mass Pike, and Emerald Necklace and the congestion in major streets such as the Boston University Bridge, Park Street, Longwood Avenue, and Brookline Avenue.


Two alternative alignments were considered: One going through Brookline along Saint Paul Street and Longwood Avenue, and the other going through Boston using Commonwealth Avenue, the Saint Mary Street Bridge, Mountfort Street, Overland Street, and Brookline Avenue. Both alternatives connect to Cambridge through the Grand Junction Bridge. The two alternatives present different pro and cons, which are presented in the table below.

Alternative 1 – Brookline Route Alternative 2 – Boston Route
Connecting subcenters + Most direct way to connect Kendall and LMA subcenters.

• 3.5 min faster

• More direct (fewer turns)

• Less congested


• More congested

• More impact on overall network

Cost + Less expensive (technically easier) More expensive (longer route)
Land use Low-density residential area

• 40% residential land

• 110 people/residential acre

• Pop. served in ¼ mi: 23,264

• Lower land values: $301/sq. ft.

Low future growth expected

+ More dense, mixed land use

• 18% residential land

• 225 people/residential acre

• Pop. served in ¼ mile: 19,523

• Higher land values: $386/sq. ft.

Higher future urban development potential

Attractions No attraction centers.

Runs through local streets

+ More attraction points (Fenway)

Runs through some main streets

Other Possible community opposition + More intermodal connections (Green Line and commuter rail)


Alternative 1 -Brookline

Serving the high residential neighborhoods along this route would require convincing low-impact design, public space improvements, and low noise (electric) buses.

Alignment Alternative 1

Alignment Alternative 1

Download the design proposals for this alignment, or view below:

Alternative 2 – Boston

Alternative 2 builds on the Locally Preferred Alternative (LPA) from the Urban Ring DEIR and seeks to balance (1) the need to connect the Kendall Square and LMA subcenters as efficiently as possible under congestion, network, and cost constraints with (2) the opportunity of serving internal trip attraction centers and intermodal connections along this portion of the route.

Alignment Alternative 2

Alignment Alternative 2

Using the Grand Junction Bridge as a Diamond Ring-exclusive way allows for a faster connection across the Charles River than using the Boston University Bridge, which has a high demand from mixed traffic.

The connection between the Grand Junction Bridge and Commonwealth Avenue is done by going underneath the Massachusetts Turnpike, crossing the commuter rail tracks, and taking Buick Street, as shown below. As a way of coping with the weaknesses identified in the comparative table above, a series of transit priority measures are proposed for Alternative 2. On Commonwealth Avenue, the Diamond Ring would run on red-painted bus-priority lanes on the right side of the street, similar to the operation of the Silver Line on Washington Street. Even though these lanes would not be exclusive to the Diamond Ring, the buses will have transit signal priority such as green phase extension when a bus is approaching the intersection. At some intersections with the appropriate geometry and queue storage lengths, exclusive right-turn lanes could be used as queue bypass lanes for buses to get ahead of other through traffic, possibly with a bus-only signal phase before the green for mixed traffic. Furthermore, parking could be restricted on Commonwealth Avenue during the peak hours to provide an exclusive lane for buses and right-turn vehicles only. Given the wide sidewalks on Commonwealth Avenue, the system can have bus stations with off-board fare collection to decrease dwell time. The stations would be located next to the BU Central and BU West Green Line Stations for easy integration between modes.

The proposed alignment would then cross the Massachusetts Turnpike again, using the Saint Mary Street Bridge. Saint Mary Street would be converted to a bus-only street, given the proximity of Carlton Street as an alternative for mixed traffic to cross the turnpike and the fact that no building has vehicular access through Saint Mary Street. This proposal requires removing 10 parking spaces on Saint Mary Street and converting Cummington Mall into a two-way street in order to provide vehicular access to Babbitt Street. A nearby alternative to the users of these spaces is parking along Cummington Mall.

After crossing Beacon Street, the Diamond Ring will cross the future Fenway Center development project through the extension of Overland Street and then take Brookline Avenue west until Park Drive. The new Fenway Center will include 300 new apartments, 370,000 square feet of office space, 150,000 square feet of retail, 30,000 square feet of public parks, and 1,290 parking spaces. Integrated with this development, the Yawkey commuter rail station is currently being remodeled and services on the Worcester Line are expected to increase in the future. The Diamond Ring would have a station at this point, connected to Yawkey Station (400 ft away) and Fenway Station (900 ft away) through a pedestrian corridor.

In order to reduce delays for the Diamond Ring vehicles due to congestion at the intersection of Brookline Avenue and Fenway, a modification to the geometry on Brookline between Fenway and Park Drive is proposed.


Major Stakeholders

This segment connects many major institutional players, including the Longwood Medical Area (LMA) and its associated hospitals, clinics, research facilities and academic institutions. The segment also serves Boston University, Fenway Park, and the Brookline Housing Authority. A number of smaller institutions and community stakeholders are located in the area, including the Isabella Stewart Gardner Museum, Simmons and Emmanuel Colleges, the Brookline Historical Society, the Emerald Necklace Conservancy, and local homeowners’ associations.


This segment passes through at least two separate municipalities: Cambridge and Boston. One of the proposed bands also traverses a third: Brookline. The Town of Brookline has publicly opposed the project. The administrative complexity inherent in this sort of border-crossing, along with the political complexity associated with so many major institutional and community stakeholders, suggest that a regional-level governance body would be the most effective mechanism for financing and implementing the Diamond Ring.

In this segment of the corridor, the primary focus areas for coordinated, multi-stakeholder planning include managing the effects of new infrastructure and development on the Emerald Necklace and other ecologically sensitive areas, promoting mixed use development to add market-rate and affordable housing to the area, and coordinating multi-modal transportation efforts to ensure pedestrian and bicycle connections to the Diamond Ring and also to coordinate with other transit service in the area.

Transportation Policy

While MassDOT and MBTA are responsible for the planning and construction of the Diamond Ring BRT system itself, the success of the system relies on proper integration with local transportation networks. This includes efforts at the municipal such as implementing proposed changes in the road network and adding or upgrading pedestrian and bicycle facilities to ensure good access to stations, particularly between stations and major destinations like Fenway Park. Institutions such as Boston University and the larger hospitals would also need to incorporate pedestrian and bicycle access to new stations as components of their campus planning. Boston University and MASCO, the transportation management agency for the LMA, may also benefit from modifying their private shuttle service to coordinate with the new service. Developers will similarly need to plan for good access to transit via pedestrian and bicycle connections around and through each new project.

Land Use & Economic Development

A governing body working along the entire urban ring corridor would also guide land use policy and economic development. Since the Diamond Ring connects major employment centers such as Kendall and LMA, policies should encourage residential and mixed-use development along the corridor in order to connect employees to jobs, particularly in areas like segment 3 that have more commercial and institutional land use than residential. Affordable housing guidelines must also be put in place to ensure that all portions of the corridor are providing their share of affordable housing.

One major development already underway is Parcel 7 near Fenway Stadium, discussed above. The proposed development will include office, residential, and retail space with connections to the Yawkey commuter rail station and the Green Line. Projects like this must be encouraged, as long as they balance new commercial space with residential uses and have appropriate connections to transit and the local pedestrian, bicycle, and roadway networks.

Branding, Messaging, and Stakeholder Engagement

A final policy area that should be managed across the project is that of engaging the affected communities. In this segment, stakeholders in Boston have generally supported the project, while those in Brookline have been strongly opposed. Working with the Brookline community to garner support for the project and to respond to their concerns is key to making the project successful. Introducing project-wide stakeholder involvement, instead of relying solely on local community-based meetings, will shift the discussion to the benefits the project will have for the region, rather than keeping a narrow focus on the local effects.

There are also ways to mitigate or reframe the effects the project will have on Brookline. Residents of Brookline are naturally concerned about capacity and service issues on the Green Line, which will be somewhat alleviated by the project. Some opponents also simply object to the branding of the project as the “Urban” Ring, since the town generally does not see itself as urban. Renaming it the Diamond Ring, in a play on the historic Emerald Necklace park system, will alleviate this concern and encourage opponents to look at the project from a different perspective.


This is perhaps the most costly segment of the Diamond Ring to implement. However, because of its many anchor institutions, including universities, hospitals, and stadiums, it also offers many possibilities for funding initial capital investment and/or system operations. For instance, the Longwood Medical Area (LMA) is already running a private shuttle bus service in this area, indicating that there is reasonable demand among LMA employees for improved transit services. This shuttle service is also entirely funded by LMA employers, indicating that if the new Diamond Ring can adequately serve employees, LMA may be able to help fund the necessary capital investments and/or system operations. In addition, other anchor institutions, like Boston University and Fenway Stadium, could help fund the system through the purchase or leasing of air rights. The sections below outline the major costs associated with this segment as well as the most promising strategies for funding the project.

Major Capital Investments

Two of the three largest capital investments for the Diamond Ring fall along this segment of the corridor. They are the Charles River Crossing and the Fenway-Ruggles Tunnel that is proposed as part of the locally preferred alternative. Successfully crossing the Charles River is absolutely essential for the success of the project. The two possible options, the Grand Junction railway and the Boston University Bridge, are both technically challenging for different reasons. While the proposed alignment uses the Grand Junction railway bridge, the use of the Boston University Bridge was considered in the initial evaluation of alignment options. The bridge was recently turned into one lane in each direction in order to incorporate bicycle lanes and currently experiences severe traffic congestion during peak hours. Successfully routing bus rapid transit through this point would require reverting the cross-section modification done recently to allow a dedicated bus lane. This may ultimately prove infeasible.

The Fenway-Ruggles Tunnel is the single largest expense for the entire project. The DEIR estimates that it would cost $1.9 billion, out of a total $2.7 billion for the project (both figures adjusted to anticipated 2015 US dollars based on a 1.5% inflation rate from $1.7 billion and $2.4 billion, respectively, in 2007 US dollars). Given the expense and the unfavorability of the current fiscal and political environment, the tunnel will almost certainly have to wait for a later stage of development. The route alternatives discussed above does not use a tunnel, though it is designed to be compatible with the addition of a tunnel in the future.

Air Rights

This segment also presents the greatest opportunity for revenue generation through the sale or leasing of the right to develop over dedicated busways and highways, so called air rights. Air rights can be a lucrative source of revenue for transportation projects and can help knit together land uses separated by major transportation infrastructure, which in turn can stimulate ridership and increase the project’s overall sustainability.

Air Rights development opportunities at the Commonwealth Avenue Massachusetts Turnpike Overpass

Air Rights development opportunities at the Commonwealth Avenue Massachusetts Turnpike Overpass

MassDOT has identified 23 “parcels” along the Mass Turnpike that could be developed via air rights. Parcels 1 through 7 run roughly adjacent to the route we are proposing. In fact, air rights are already being used to build the “Parcel 7 Fenway Center” mixed-use development over the Mass Turnpike near Yawkey Station, as discussed above. The leasing of air rights to private developer Meredith Management Corporation will yield $5.5 million upfront for MassDOT and a total of $226 million over the life of the 90-year lease.

The intersection between the BU Bridge and Commonwealth Avenue offers particular promise for this model of revenue generation. As shown in the image below, the northwest and southeast corners of the intersection are currently undevelopable, as the Mass Turnpike passes underneath. Covering the Turnpike in those two areas could create an additional 73,000 square feet of developable land.

Station Adoption

The many major institutions located along this segment of the corridor also present an opportunity to fund the development of iconic stations. Boston University, the many hospitals that form the Longwood Medical Area, Fenway Stadium, and other major players may wish to fund iconic stations in order to support local streetscape enhancements and transit access for their students, employers, or visitors. Cleveland has had success with this model: In 2008, Cleveland Hospitals paid $6.25 million for the naming rights of the so-called HealthLine. In the case of the Diamond Ring, constructing iconic stations with pre-boarding and card-charging facilities could be essential to successfully branding the line and improving travel times.

Employer Transportation Levy

An employer transportation levy that targets firms or organizations with over 500 employees could be particularly effective in this area: a conservative 0.05 percent levy would generate $11.3 annually from the Longwood Medical Area alone. Targeting large employers would allow for the system to generate revenue without negatively impacting existing and future small businesses along Washington Street and elsewhere in this area.

Next Steps

Implementation of these proposals requires additional analyses on a variety of topics. The most important of these topics are discussed here.

The proposed alignment and corresponding transit priority strategies require a detailed analysis using traffic micro simulation tools. In order to do this we need detailed information on traffic volumes, traffic signal operation, commuter rail and Green Line operation, and estimated Diamond Ring boardings. A more detailed design of the Diamond Ring stations is also required in order to represent boarding times more accurately in the simulation.

We require more detailed cost estimates for the major infrastructure investments required along this segment. Our proposal to expand and repurpose the Grand Junction Bridge was not explicitly studied in the DEIR and requires further investigation in order to assess its ultimate feasibility and cost.

The proposed alignment examined in this report does not include the Fenway-Ruggles tunnel that made the locally preferred alternative cost-prohibitive. However, the proposed tunnel is the best way to handle the long-term increases in congestion and corresponding decreases in service quality along the Diamond Ring that will result from future growth and development in the Longwood Medical Area. Studying when and how the tunnel might be constructed and how it might be funded is important to the long-term success of the Diamond Ring.

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