The Silver Line BRT from Boston's South Station to the South Boston Waterfront and on to Logan international Airport, utilizes the I-90 Ted Williams Tunnel and it's own dedicated right-of-way under the Fort Point Channel, both completed as part of Boston's "Big Dig." The new, reliable, high-capacity transit connection it provides helps to unlock the development potential of a large, underutilized part of Boston, which was previously cut of from the downtown core.
Project Type:New Line Project Mode:Bus Rapid Transit Average Weekday Riders:16,056 Length (mi):8.90
Economic Distress:1.02 Population Density (ppl/sq mi):11678 Population Growth Rate (%):61.00
Employment Growth Rate (%):672.00 Market Size:5,819,100 Airport Travel Distance:3 Topography:4
Region:New England/Mid-Atlantic State:MA County:Neighborhood
City:Boston Urban/Class Level:Core Local Area:Zip Code 02210 (South Boston Waterfront)
Impact Area:Within 3/4 mile of station(s) Transportation System:N/A GIS Lat/Long:42.355912 / -71.038729
Initial Study Date:1997 Post Constr. Study Date:2012
Constr. Start Date:1995 Constr. End Date:2005
Project Year of Expenditure (YOE): 2001 Planned Cost (YOE $):508,000,000
Actual Cost (YOE $):625,000,000 Actual Cost (curr $):822,123,800
NOTE: All pre/post dollar values are in 2013$
Select a region to display the conditions for that region:
NOTE: All impact dollar values are in 2013$
|Income (in $M's)||410.10||0.00||410.10|
|Output (in $M's)||726.40||0.00||726.40|
Boston’s Silver Line Waterfront BRT was developed as part of the suite of projects to improve transportation capacity and access in the core of Boston. Silver Line construction began in 1995 and by its completion in 2005 growth was already accelerating. These projects were collectively known as the Central Artery project or the “Big Dig.” Boston has one other rapid transit line that is also marketed as Silver Line BRT, which opened two years earlier and runs along Washington Street in another part of the city. The Silver Line provided the first rapid transit access to South Boston’s waterfront, using specialized dual-mode diesel/electric trolleybuses that operate mostly in dedicated right-of-way. Along with other infrastructure components of the “Big Dig” and supportive land use planning, the Silver Line has helped to drive rapid development and growth in South Boston. The Silver Line brings about half as many new commuters to the Waterfront every morning as the highway access added on I-90. Assuming a significant development impact of supportive land use and regional revitalization efforts, the Silver Line seems likely to be directly responsible for about 3,350 jobs.
2.1 Location & Transportation Connections
The Silver Line Waterfront BRT connects South Boston with downtown Boston’s South Station as well as Logan International Airport. South Boston lies to the south east of the core neighborhoods of Boston across the Fort Point Channel. The Airport is northeast of South Boston, across the main harbor.
Silver Line Waterfront service is currently made up of two routes with four shared stops. These four stops use a dedicated transitway in order to cross below the Fort Point Channel between South Station and waterfront. The routes diverge at the fourth station to head toward the airport or Boston Marine Industrial Park.
The South Station stop provides connections to MBTA’s Red Line, numerous commuter rail lines, and Amtrak service to the Northeast Corridor. Original plans were to connect the Silver Line to the Orange Line and Green Line subways west of South Station, as well as the Washington Street Silver Line BRT. Budgetary concerns have put this connection project on hold indefinitely. Work is proceeding to extend a Silver Line route past the airport where it will connect to the Blue Line subway and then enter downtown Chelsea and an additional commuter rail line.
The Silver Line’s many connections create a link between the South Boston Waterfront and significant portions of the metro region with a 2-seat ride on public transportation.
2.2 Community Character & Project Context
South Boston’s waterfront in the 1990s was physically and socially cut-off from downtown Boston by the elevated central artery which carried I-93 and I-90 through Boston. A majority of the area was surface parking and light industrial sites. Considering its close proximity to Boston’s core neighborhoods, South Boston offered some of the least utilized land in the metro area. The Central Artery project removed the physical barrier between the Financial District and South Boston and replaced it with the Rose Kennedy Greenway. The I-90 extension significantly increased highway access in South Boston. These infrastructure changes along with the new transit access provided by the Silver Line accelerated a transformation of the area which began during the early planning stages of the transportation projects.
Planning for the Silver Line Waterfront service began around the time that the Big Dig was approved for federal funding in 1987. The transit improvements would become considered part of the suite of projects to untangle transportation in downtown Boston. Many developers and planners considered South Boston ripe for growth given it’s adjacency to the relatively built-out downtown, but improved access was sorely needed. Improved transit connections would be just as important to development as improved highway capacity given regional commuting patterns. Parking is capped in South Boston by a parking freeze and commuters continued to deal with peak period congestion in Boston even after the Big Dig solved some of the most significant problems.
The Silver Line project operates in a tunnel bored from South Station under the Fort Point Channel and onto the Courthouse and World Trade Center stations. From the World Trade Center station to the Silver Line Way station, the Silver Line uses dedicated aboveground right-of-way, after which point it splits into two routes. The SL1 route to the airport shares the Ted Williams Tunnel under the Boston Harbor with I-90 traffic to reach its five airport stops, while the SL2 continues on surface roads through the Boston Marine Industrial Park.
The Silver Line Waterfront project included significant renovations to South Station, as well as the construction of two new belowground stations at the Courthouse and World Trade Center stops. These new stations are generally considered to be more elaborate than most of the subways stations on MBTA’s heavy rail lines. These station locations were sited to be centrally located with respect to anticipated future development projects.
The necessity for construction of tunnels and underground stations raised construction costs of the Silver Line. The final project cost was around $625 million in 2001 dollars, including professional services, construction, rolling stock and a maintenance facility for the dual-mode buses required for the service. This exceeds the cost estimate from the 1993 Full Funding Grant Agreement with FTA by about 25% after adjusting for inflation. Part of this cost increase was due to several construction delays that stretched the construction period out over 10 years.
4.1 Transportation Impacts
Before the Silver Line’s opening, the transit mode share in South Boston stood at roughly 15 percent. Today 27 percent of trips to, from and within the area are on transit, mostly the Silver Line. FTA estimates that transit trips to the waterfront doubled in the first two years of operation, partially due to mode shift and partially due to new riders – reflecting the rapid growth in local employment.
Average daily ridership in 2014 stood at 16,000 on weekdays and 10,000 on weekends. This is around three times the previous transit ridership, or nearly 10,000 new weekday transit trips to/from South Boston. Around 20 percent of riders are traveling to the airport on weekdays and not stopping in South Boston. Weekend ridership continues to grow year-over-year as people use the Silver Line to reach the area’s expanding retail and cultural destinations. On weekdays, the Silver Line is nearly at capacity, due to limited rolling stock availability, which prevents increasing the frequency of service on the line. This limits additional ridership growth.
Automobile use continues to be higher in South Boston than other parts of the urban core, which significantly more travelers can reach with by transit without a transfer between lines. However, the Silver Line has significantly improved multimodal access to the waterfront and the airport.
South Boston’s residential population is growing, but Silver Line ridership remains highly skewed towards a single direction in during morning peak and out with the evening peak as commuters arrive or depart from jobs in the district. Currently morning peak-hour ridership from South Station to the Waterfront is around 1,400, while evening ridership back to downtown and its connections with commuter rail and the Red Line is nearly 1,200 passengers per hour. In comparison about 2,800 vehicles per hour use the new I-90 interchanges in South Boston in the morning, and 2,200 during the evening peak.
The Silver Line has not significantly improved travel times to the waterfront relative to previous local bus routes, but it offers significant increases in reliability and service frequency. Under the Institute for Transportation & Development Policy’s BRT Standard, the Silver Line does not qualify as bus rapid transit. The major areas of deficiency relative to the standard are that it requires on-board fare collection (at the Silver Line Way station), does not offer level boarding, and operates in dedicated right-of-way for the minority of the route.
Other limiting factors on the Silver Lines transportation impact include the need to switch from overhead electric to diesel power and the 25mph speed limit in the tunnels. The MBTA and other agencies have been working together since the line’s completion to continue to improve its effectiveness. Improvements have been made on signal prioritization, and additional efforts are underway to smooth some of the Silver Line’s operations in traffic. Free fares on the return trip from Logan Airport have also significantly improved station dwell times.
4.2 Demographic, Economic & Land Use Impacts
The earliest growth in the Seaport District was anchored by several large public buildings. The $170 million Moakley U.S. Courthouse opened just several years after construction began on the Silver Line. The year before the Silver Line’s completion, in 2004, the $800 million Boston Convention and Exhibition Center welcomed its first guests. In 2006 the $75 million Institute of Contemporary Art offered another cultural attraction.
The BCEC and World Trade Center convention space have helped to attract hotels, retail, restaurants and entertainment to the waterfront. Hotels supporting these destinations were some of the first major additions to the area with about 1,350,000 square feet of hotel space being added between 2000 and 2013. Plans for additional hotels may eventually provide the city with over $1 billion annual in new hotel tax revenue. In 2013, 1.8 million more people visited South Boston’s key attractions than in 2000. Many of these visitors brought new spending to the local economy.
As hotel and meeting space has expanded, so have retail, office, and residential spaces. From 2000 to 2013, retail square footage increased by 70 percent as new restaurants and stores opened. Future planned development will include significant street-level retail offerings in many of the new buildings, and sometimes additional floors of retail.
The residential population in the Seaport District has increased over 60 percent from 2000 to 2013, by 4,100 people. Future construction plans approved by the Boston Redevelopment Authority would potentially allow another 16,000 people to move into the neighborhood, with a final population of 4 times the pre-“Big Dig,” pre-Silver Line area.
Job growth is expected to follow a similar trajectory. Already around 15,000 new jobs have been created in South Boston, and some of the largest developments are now under construction. A full build-out of the area could add 52,000 jobs to the 20,000 that the U.S. Census Bureau identified in the 2000 County Business Patterns survey, partway through the Silver Line’s 10-year construction. A significant portion of these jobs are in high-tech industries and professional services, including computer technology, medical research, pharmaceuticals, finance, and other high paying professions.
Because of the large scale of many of the development projects in the Seaport District, as well as, the effect of the 2008 recession in suppressing growth, some of the most significant changes in the area are only beginning to take place now, ten years after the Silver Line first opened. Rapid transit access to the region and the efficiency of buses operating in dedicated right away removed from the curbside, has been an important factor during the planning of many of the regions developments. With only the addition of highway capacity, many of the higher density land uses that have been developed or are planned would not be possible.
Based on the peak period split between the I-90 ramps and Silver Line, a conservative estimate of the impact of the new transit access on employment could claim 5,000 jobs to date. The long-term employment impact of the Silver Line if only major transportation infrastructure improvements are considered could reach 18,000 jobs.
There are two other important factors which have influenced South Boston Waterfront and especially the slightly smaller Seaport District sub-area to develop, and which should be considered in the attribution of economic impacts.
The first is largely an aesthetic and community dimension, while the second is the application of proactive and supportive planning efforts. Boston’s harbor resources have been undergoing a long-term revitalization as the city works to clean up the main harbor and channels. Improving the quality of the harbor and beginning to think of it as part of the space rather than peripheral to it has increased the value of waterfront property for residents, businesses, and visitors. Besides transportation improvements from the I-90 ramps and Silver Line, the Central Artery also removed a physical and visual barrier between downtown and South Boston that makes the two areas more cohesive and thus facilitates travel between them.
The second major factor has been the involvement of the Boston Redevelopment Authority and other city, regional, and state agencies in supporting land use change in South Boston. Much of South Boston is governed by state tideland regulations as well as being made up of designated port areas and other regulations affecting development. Most of the projects completed and planned for South Boston are governed as individual “planned development areas,” which provide zoning overlays and provide the public sector input into project’s specific implementation without placing all projects into a single category. There are also area-wide planning efforts such as the 1999 Public Realm Plan, 2000 Transportation Plan, and 2015 Sustainable Transportation Plan that support the area’s growth as a whole.
Assuming these efforts have supported about one third of total growth to date and at final build-out of the waterfront area, leaves about 3,350 current jobs attributable to the Silver Line and 12,000 jobs in the long-run.
A Better City. 2015. South Boston Waterfront Sustainable Transportation Plan.
City of Boston. 2002. Access Boston 2000-2010.
Federal Transit Administration. 2007. Silver Line Waterfront BRT Project 2007 Evaluation .
Economic Development Research Group. 2006. Real Estate Impacts of the Massachusetts Turnpike Authority and the Central Artery/Third Harbor Tunnel Project.
Breakthrough Technologies Institute. 2008. Bus Rapid Transit and Transit Oriented Development: Case Studies on TOD Around BRT Systems in North America and Australia.
A Better City
Boston Redevelopment Authority
Case Study Developed by Economic Development Research Group, Inc.