Massachusetts Coalition Calls on State to Switch to Electric Buses

Along with the Zero Emission Bus Coalition -- a collective of environmental, transit, labor, community, and public health organizations dedicated to accelerating the electrification of public transit - we delivered this letter to Massachusetts Governor Charlie Baker, Secretary of Transportation Stephanie Pollack and the Chairman of the MBTA’s Fiscal Management and Control Board, Joseph Aiello calling for a clear commitment to transition the MBTA to all-electric buses. 

Matt Casale

Former Director, Environment Campaigns, PIRG

December 5, 2019

Re: Expedite the Transition to a Zero Emission Electric Fleet at Massachusetts Bay Transportation Authority (MBTA)

Dear Governor Baker, Secretary Pollack, Chairman Aiello, and esteemed members of the Fiscal and Management Control Board (FMCB):

The undersigned members of the Zero Emission Vehicle (ZEV) coalition submit these comments in response to the Bus Fleet and Facilities Plan updates and on the creation of a Bus Transformation Office. The Zero Emission Vehicle coalition (ZEV) is a collective of environmental, transit, labor, community, and public health organizations dedicated to accelerating the electrification of public transit and vehicle fleets.

Transportation emissions have been on the rise nationally, and already in 2016 represented 43% of greenhouse gases (GHG) emissions in Massachusetts.[1] The latest climate science tells us that at the current GHG emission rates, and with a limited global carbon budget left at our disposal, we have a 50% chance to keep the global temperature rise limited to +1.5 degrees Celsius only if we collectively stop emitting GHG by 2030, and reach net-zero globally around 2050.[2] These requirements are even more stringent than what the Massachusetts Global Warming Solution Act is set to achieve.                                                 

As stated in the report to the Governor from the Commission on the Future of Transportation, the decarbonization of the public transit sector is a critical step to achieve the Commonwealth’s 2050 GWSA mandate. In addition to reducing climate-warming emissions, the elimination of all fossil fuels – both diesel and compressed natural gas – from public transit buses has enormous co-benefits for air quality and public health. Diesel exhaust, in particular, is known to contain more than 40 toxic contaminants and potential carcinogens, and is a recognized hazard to human health.[3] Pollution control technologies as those deployed on diesel-hybrid buses do not entirely eliminate diesel exhaust, and leave behind ultrafine particles containing soot and heavy metals that are a serious threat to human health.[4],[5] Diesel fuel is also a documented occupational hazard for the workforce – fuelers, garage and maintenance workers – subjected to routine exposure.[6] The complete removal of diesel exhaust from the air we breathe is of paramount importance.

We commend the MBTA for deploying the first 5 battery electric buses on the Silver Line, including on routes that run through Chelsea, a disadvantaged community burdened by high asthma rates. We are pleased that the initial performance of the battery electric buses has met expectations. We ask that the plan to test these buses for two years[7] is shortened to a one-year pilot, in order to accelerate the transition to battery electric buses.


As suggested by the recent Bus and Facilities plan, we are indeed concerned that MBTA will continue to procure significant numbers of fossil fuel buses in the next 5 years. In addition to the 194 diesel hybrid buses that will replace the 2004-2005 fleet, MBTA is exploring options to add additional diesel- hybrid buses to the Dual Mode Articulated (DMA) fleet in 2020. Furthermore, the 2021‑2024 Capital Investment Plan (CIP) outlines the purchase of up to 750 buses for both fleet replacement and expansion. Given that buses purchased today will remain in service for at least another 12 years, it is critical that MBTA introduces electric buses as the old diesel fleets are retired. In addition to the electrification of the North Cambridge facility where the first 35 buses will be housed, the planned replacement and expansion of the Dual Mode Articulated (DMA) fleet provides MBTA with an opportunity to move away from fossil fuel procurements and invest in clean electric buses in a timely manner. In addition, at least half of the bus procurements mentioned in the 2021-2024 CIP should be electric.


Electric buses are an advantageous long-term investment for the following reasons:


  • Electric buses are four times more efficient than the fossil fuel counterparts, and therefore offer the greatest opportunity to reduce lifecycle carbon emissions.[8]
  • Conversely, advanced hybrid buses have only a 30% higher fuel efficiency compared to the older diesel vehicles[9] – therefore can only reduce GHG emissions by 30%. Moreover, pollution control technologies in diesel-hybrids do no not mitigate ultrafine soot particles and carcinogenic gases such as benzene and Polycyclic Aromatic Hydrocarbons (PAHs). Finally, recent studies have shown that even the most modern diesel-hybrids do not perform as expected under real-world conditions in terms of nitrogen oxides (NOx) emission reduction.[10] 
  • Electric bus technology has much lower maintenance costs than a combustion engine, and when paired with smart charging strategies and favorable time-of-use rates, it can save thousands of dollars over the lifetime of the bus. For instance, electric buses have saved the Chicago Transit Authority more than $50,000 every year in fuel and maintenance costs.[11]
  • Electric bus technology has improved enormously and is quickly becoming mainstream and there is performance data available from electric buses operating across North America and Europe. In the last two years, electric buses have also demonstrated the capability to deal simultaneously with cold weather and steep grades.[12] 

We are aware that the transition to electric bus fleets is dependent on the availability of adequate garage facilities and we acknowledge MBTA’s ongoing efforts to address existing deficiencies with multiple garages. MBTA must commit to a clear timeline for upgrading existing facilities and building new ones and ensure that all facilities – starting with the Southampton, Albany and Quincy garages – are equipped with the necessary power and infrastructure requirements to host battery electric bus fleets. Quieter, diesel-free garages will no longer be a nuisance for the communities hosting them and will significantly improve MBTA’s employees working conditions.

The MBTA should also consider adding solar generation capability and battery storage units at the garage locations to increase power resilience and cut costs associated with demand charges; several agencies, including Martha’s Vineyard Transit Authority, are actively looking at these options while scaling up their electric bus fleets.[13],[14]

It is also critical that the MBTA honors the state’s Environmental Justice policy[15]by prioritizing electric bus deployment in communities such as Chelsea, Lynn, Roxbury, and Dorchester that are already disproportionately burdened by congestion and pollution. Residents of these areas rely heavily on buses and yet are severely underserved, as outlined in the recent Livable Street Alliance report ’64 Hours: Closing the Bus Equity Gap’.[16] Because these communities should be the first to be relieved from diesel pollution, we recommend that battery electric bus deployments are prioritized in the environmental justice areas of metro Boston, consistent with the procedures followed by other transit agencies in the U.S., such as San Francisco SFMTA.[17]

We look forward to seeing a clear timeline and a pathway for a transition to an electric fleet in the long-awaited bus electrification feasibility study. Transit agencies operating in major U.S. cities including Seattle, New York, Chicago, Minneapolis, San Francisco and Los Angeles have already committed to full fleet electrification by 2035 or 2040.  MBTA should do the same. Without a clear timeline, the required planning and momentum for full fleet electrification will continue to be delayed.

In summary, we ask the MBTA to:

  • Limit the testing period for the five electric buses that were introduced in the summer of 2019 to a one-year pilot (until summer 2020).
  • Commit to replace the Dual Mode Articulated (DMA) fleet and at least half of the bus procurements mentioned in the 2021-2024 CIP fleet with battery electric buses or other technology with zero tailpipe emissions.
  • Commit to clear short-term (5 years) and long term (10-15 years) goals and a timeline to upgrade existing and build new garage facilities to support fully electric bus fleets. Expedite the work at the Southampton and Quincy garage facilities to start hosting electric bus fleet by 2022.
  • Commit to all electric bus purchases starting 2030 and complete fleet electrification by 2040
  • Prioritize the deployment of electric buses on routes that serve environmental justice communities to deliver a much-improved service in areas that are disproportionately impacted by air pollution while being most dependent on public buses. 

Finally, we are pleased by the FMCB decision to establish a Bus Transformation Office to “develop and implement environmental, financial, procurement, and operational strategies and others as required” to significantly improve the bus service in and around Boston. Heavily investing in electric buses should be a key component of the transformation of the bus system to deliver a modern service and a better rider experience. The MBTA should also take advantage of the creation of such office to stay abreast of other clean vehicle technologies such as In Motion Charging (IMC), which could be piloted on existing electric trolley lines and deployed along fixed bus priority corridors. 

We respectfully urge MBTA to act boldly by changing the current direction of investment in the bus fleet towards electric technologies in a timely manner.

Thank you for your time and consideration


Veena Dharmaraj, Sierra Club, Massachusetts Chapter

Eugenia Gibbons, Green Energy Consumers Alliance

Matthew Casale, Massachusetts Public Interest Research Group

Nancy Goodman, Environmental League of Massachusetts

Leah Robins, Metropolitan Area Planning Council

Sylvia Parsons, 350Mass Transportation Working Group

Edward Hsieh, Asian American Civic Association

Jordan Stutt, Acadia Center

Staci Rubin, Conservation Law Foundation

Daniel Gatti, Union of Concerned Scientists

Corey Alperstein, 350Mass, Newton Node

Eleanor Fort, Green For All

Alicia Bowman, Bike Newton

Maria-Belen Powers, Green Roots Chelsea

Marcia Cooper, Green Newton

Julia Wallerce, Institute for Transportation & Development Policy

Mela Bush-Miles, Alternatives for Community and Environment

Mike Vartabedian, International Association of Machinists and Aerospace Workers

Jarred Johnson, TransitMatters

Ben Hellerstein, Environment Massachusetts

Burton Jaffe, The Environmental Forum



[1], MA GHG Emission Trends: MA and US GHG by Sector.


[2] IPCC, 2018: Summary for Policymakers. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of

global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in

the context of strengthening the global response to the threat of climate change, sustainable development, and

efforts to eradicate poverty World Meteorological Organization, Geneva, Switzerland, 32 pp.


[3] California Office for Environmental Health Hazard Assessment (2001). Health Effects of Diesel Exhaust.


[4] DPF Solution Sheffield, UK. (2016). New DPF Filter Effectiveness Queried by Scientists.


[5] Lane, K.J., et al. (2016). Association of modeled long-term personal exposure to ultrafine particles with inflammatory and coagulation biomarkers. Environ Int.


[6] National Council for Occupational Safety and Health (n.d.). Diesel Hazards.


[7] MBTA (July 31, 2019). First Zero-emission Battery-electric Buses Join the MBTA Silver Line Fleet.


[8] O’Dea, Jimmy (2018). Electric vs. Diesel vs. Natural Gas: Which Bus is Best for the Climate?


[9] M.J. Bradley & Associates, LLC. (2013). Comparison of Modern CNG, Diesel and Diesel Hybrid Electric Transit Buses: Efficiency and Environmental Performance.


[10] Yang, L. et al. (2016). Evaluating real-world CO2 and NOX emissions for public transit buses using a remote wireless on-board diagnostic (OBD) approach. Environmental Pollution, Vol. 218, 453-462.


[11] U.S. PIRG (2019). Electric Buses in America. Lessons from Cities Pioneering Clean Transportation.

[12] Lambert, F. (April 18, 2018). Proterra puts its all-electric dual motor bus to a tough test on Utah’s steepest roads.


[13] Shemkus, S. (December 10, 2018). Martha’s Vineyard transit plan goes beyond electrification.


[14] Anderson, K. (April 19, 2019). Resiliency or sustainability: Which is most Important when designing for transit agencies.


[15] (January 31, 2017). Environmental Justice Policy of the Executive Office of Energy and Environmental Affairs.


[16]  Livable Streets Alliance. (September 2019). 64 Hours: Closing the Bus Equity Gap.


[17] Fracassa, D. (October 2, 2019). Muni tries to tackle environmental justice with new SF green bus zones.


Matt Casale

Former Director, Environment Campaigns, PIRG