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Greenhouse Gas Reduction

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Photo of Red Line traveling over the Longfellow Bridge in Boston with sail boats underneath on the Charles River (photo courtesy of the MBTA)

Greenhouse Gas Reduction

The Commonwealth of Massachusetts and MassDOT are committed to reducing greenhouse gas (GHG) emissions, which contribute to global climate change. The Commonwealth’s Global Warming Solutions Act, signed into law in 2008, set the legally-enforceable goals of reducing GHG emissions by 25 percent below 1990 levels by 2020, and 80 percent below 1990 levels by 2050.

In January 2015, the Massachusetts Department of Environmental Protection (DEP) promulgated 310 CMR 60.05: Global Warming Solutions Act Requirements for the Transportation Sector and the Massachusetts Department of Transportation (the “GreenDOT Regulation”). This regulation places a range of obligations on MassDOT and Metropolitan Planning Organizations (MPOs) to further the achievement of the Commonwealth’s climate change goals through the programming of transportation funds. These obligations include, but are not limited to, the following:

  • MPOs must use GHG impact as a project selection criterion when reviewing projects to be programmed in the TIPs/STIPs.
  • MassDOT must evaluate and report on the total GHG impact of the State Transportation Improvement Programs (STIP) on a yearly basis, measuring those impacts against the reduction goals set out in the Global Warming Solutions Act (GWSA) process.

MPO GHG Assessment and Reporting Guidance

MassDOT and the Commonwealth’s Metropolitan Planning Organizations (MPOs) have been assessing and publishing Transportation Improvement Plans’/State Transportation Improvement Programs’ (TIP/STIP) greenhouse gas (GHG) impacts since the 2013-2016 STIP process in an effort to better understand how project programming and funding decisions increase or decrease transportation sector GHG emissions. These impacts have been reported as STIP appendices each year.

The promulgation of the GreenDOT Regulation led the MassDOT Office of Transportation Planning to evaluate how MassDOT and MPOs were assessing and reporting the GHG impacts of TIP/STIP projects. This evaluation identified several areas that could benefit from detailed guidance to improve data quality and consistency. Working with the MPOs, the Office of Transportation Planning developed a guidance document that provides standard methodologies to address these issues.

More information about the background of the GWSA can be found at the Executive Office of Energy and Environmental Affairs. For more information about progress toward GHG reduction goals, please see the page on Measuring Progress in implementing the GreenDOT Policy. MassDOT promotes eco-driving through the MassRIDES Drive Smart and Save campaign and by including green driving tips in the RMV’s Driver’s Manual (PDF 3.89 MB, on page 131).

Modeling GHG Reduction Policies

MassDOT received a grant from the Federal Highway Administration to demonstrate the use of their Energy and Emissions Reduction Policy Analysis Tool (EERPAT).

This tool is a system of disaggregate household-level models that better accounts for interactions between policies than simpler sketch methods. EERPAT also accounts for feedback from congestion and household travel costs. EERPAT offers more flexibility to model potential GHG reduction measures than traditional travel demand models.

The objectives of this project were to demonstrate a tool that could be used by Metropolitan Planning Organizations (MPOs) to help include consideration of GHG emissions in planning efforts and to provide information on the potential GHG benefits of a variety of GHG reduction measures and the potential costs of implementation.

MassDOT’s consultants Cambridge Systematics, with support from Oregon Systems Analytics and the Boston MPO’s Central Transportation Planning Staff, populated the tool with Massachusetts specific demographic and transportation system inputs and calibrated the tool against actual household income, vehicle registrations, vehicle miles traveled and motor fuel sales in Massachusetts. The model was spatially aggregated to the level of Metropolitan Planning Organizations.

The tool was used to model policies including investments that a State DOT and MPOs could make (such as transit, cycling infrastructure, employer travel demand management programs, and intelligent transportation systems) as well as other policies beyond the reach of a State DOT but that are cited as potential approaches to GHG reduction (such as Low Carbon Fuel Standards, parking pricing and land-use regulation).

MassDOT made the Massachusetts specific version of this tool available to Massachusetts Metropolitan Planning Organizations and provided hands-on training to enable them to use EERPAT as part of their long range planning efforts as appropriate.

A copy of the final report detailing the modeling conducted by Cambridge Systematics during 2015 and 2016 is below.

To learn more about the EERPAT model and other examples of its application, visit the FHWA EERPAT website

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