CHAPTER 3

Review of Current Practice, Methods, and Tools

Review of Current Practice

The project team reviewed current practice in addressing GHG emissions and climate change effects in environmental reviews, as well as environmental justice and equity considerations specific to those topics. The review focused on the following topics:

• Federal requirements and guidance related to the consideration of GHG emissions and climate change impacts, including equity effects, in NEPA procedures and documentation. This included guidance from the CEQ as well as U.S. DOT and its modal administrations. Midway through the project (January 2023), the CEQ issued its interim NEPA Guidance on Consideration of Greenhouse Gas Emissions and Climate Change.
• State requirements and guidance for the consideration of GHG emissions and climate change impacts, including equity effects, in NEPA documentation as well as per State environmental review requirements. The project team identified 11 States with published guidance on considering GHG emissions, in most cases DOT guidance published as part of a NEPA and/or air quality guidance document; and 4 States with published guidance addressing consideration of climate change effects. The January 2023 interim guidance issued by CEQ has led a number of States to develop or update their approaches. It is anticipated that additional States will develop guidance on these topics, and States with existing guidance may develop updates, in the time following publication of the guide.
• Other relevant guidance and resources related to the consideration of GHG emissions and climate change impacts in environmental reviews, including academic research.
• Examples of environmental documents, to identify procedures applied in practice and the conclusions that have been drawn. The project team reviewed summary information in the U.S. Environmental Protection Agency (EPA) on 89 NEPA Final Environmental Impact Statement documents for projects or programs where a transportation agency was the lead agency were issued (with a notice published in the Federal Register) between 2016 and 2021. The team also performed a more detailed review of 21 EIS documents to examine how GHG emissions and climate change effects were evaluated and documented. While the scope of the review was largely related to environmental reviews for transportation projects, it also covered requirements and guidance related to transportation planning and programmatic-level reviews.

The substantive findings of the review are summarized in Section 2.0 of the guide. Appendix A of the guide provides a complete, annotated bibliography of the sources reviewed. Appendix B of the guide (attached as an Excel® workbook) provides a detailed review of 21 environmental documents.

The project team drew the following conclusions regarding current guidance and practices for addressing GHG emissions, climate change effects, and related equity issues in transportation environmental reviews:

• Federal environmental law accommodates the consideration of GHGs and climate change effects in NEPA, especially since the 2007 ruling establishing GHG as an air pollutant. However, Federal guidance on these topics has only existed (at least in draft form) since 2010, and continues to evolve with changing administrative priorities. The current (2023) CEQ interim guidance, while providing the most specific

• guidance issued to date, still appears to leave substantial latitude in how GHG emissions and climate effects are addressed for any particular project.
• Federal direction on environmental justice was first established in the 1990s and emphasis and guidance from Federal agencies, including U.S. DOT and modal administrations, has continued to evolve since that time. However, this guidance has not specifically addressed linkages between GHGs or climate impacts and environmental justice. As of 2021, the current Administration is placing a much greater emphasis on consideration of equity in Federal programs, including discretionary transportation grant programs.
• At least 11 States have adopted written guidance on addressing GHG and/or climate effects in federally or State-required environmental review, mainly focusing on GHG emissions. The range of approaches varies from purely qualitative (including referencing to statewide assessments), to requirements for quantitative GHG analysis for projects meeting certain criteria. Other States may have informal policies or no policies at all, making decisions on a project-by-project basis.
• Based on a review of documents from the past decade, consideration of GHG emissions in environmental review, including quantitative assessment, appears to be increasing. Consideration of climate effects also appears to be increasing and becoming more robust, considering a broader range of stressors. To date there have been few or no instances of linking GHG, climate, and equity issues in environmental documentation. There continues to be a very wide range of approaches to how GHG and climate are considered in NEPA reviews.
• The most challenging aspect of including climate change under NEPA is drawing a conclusion, especially absent any guidance about what scale of effects might be considered significant. Most project documents that consider GHG have concluded either that emissions would be reduced; or that emissions effects would be insignificant in proportion to statewide, national or global emissions; or that other agency or sectoral efforts to reduce emissions would eventually address the problem; or that no conclusions can be reached given not having guidance on significance.
• Numerous legal challenges have been brought under NEPA or State laws that have included climate change; environmental review documentation is clearly vulnerable to litigation on climate grounds. The challenge of meaningfully addressing climate change at the project level, not having detailed and final guidance, and the great variability of when and how climate change is addressed in environmental review from project to project and across the U.S. likely all contribute to this vulnerability.

Review of Tools and Methods

The project team also reviewed available methodologies and tools for analyzing GHG emissions and climate change effects related to transportation projects. The review considered three general types of tools:

• Tools for estimating GHG emissions related to a project. The review of GHG estimation tools included 23 tools for developing baseline forecasts and evaluating project alternatives and mitigation strategies. Tools were reviewed to estimate emissions from direct (tailpipe) and life-cycle emissions from the operation of vehicles on the facility, as well as from construction and maintenance activities.
• Tools for identifying potential future climate changes and effects in the project area. The review included 33 tools that provide climate data and projections (e.g., sea level rise, precipitation, storm surge, temperature, fires, and smoke) or can assist with assessing climate impacts (e.g., flooding areas, infrastructure impacts, population and economic impacts).
• Tools for screening for equity effects, including environmental justice and overburdened and under-resourced populations. The review included 15 tools and methods for defining reference populations and identifying risks from environmental effects.

The review mainly focused on tools available nationwide, that any States could use, but also included examples of State-specific tools. State tools were included to provide examples of what individual States have developed to suit their own needs and fill gaps in the available national tools. Appendix C of the guide

The national tools also include programs that can be used to model complex processes relating to coastal change (e.g., the Sea Level Rise Affecting Marshes Model; the Coastal Storm Modeling System) and watershed hydrology and stream flow (e.g., the Precipitation Runoff Modeling System; the National Climate Change Viewer). Some of the tools also incorporate socioeconomic data, which can be helpful in identifying potential impacts in a project area for populations at greater risk from climate change impacts.

The State tools, while only directly applicable to projects and planning efforts in an individual State, provide useful examples of ways that States can use climate information to tailor their own decision-making support tools. For example, Florida’s Sea Level Scenario Sketch Planning Tool identifies exposure of infrastructure to current and future flood risks under various U.S. Army Corps of Engineers and NOAA sea level rise scenarios. The California Energy Commission produced a variety of tools through CalAdapt, a centralized website housing climate data for the State of California. The Maryland DOT developed a geographic information system application that identifies sea level rise and flooding impacts to roads throughout the State.

Equity Assessment Tools

The project team reviewed national tools, State tools, and one Metropolitan Planning Organization (MPO) tool used in equity assessments. The tools reviewed vary in terms of functionality. Many of the tools, particularly the older tools reviewed, provide the ability to view data. All of the equity tools provide insight into equity issues at varying levels of geography, including county, city, State, census tract, census block group, coordinates, and address. For users looking for equity information on a specific project location, most tools would require users to navigate to a known project location and find relevant project location (for example, by finding a county on a map). A handful of advanced tools allow the user to interact with the tool to find relevant project information by selecting a point, line, polygon, or rectangle on the map to query custom areas (both by area and by relationship, and with and without a buffer). The ability to select a more detailed geographic area could support a more focused analysis around a specific project area (for example, to evaluate the air quality impacts adjacent to a planned highway expansion), where a county-level analysis might be more useful to assess regional impacts.

All of the tools reviewed could be used during project screening and outreach to better understand the socioeconomic characteristics of the project area. However, most would not support an analysis specifically of environmental justice effects conducted under NEPA. For example, many of these tools are able to provide summary information for a group of block groups, but do not support the analysis required to determine which block groups meet low-income and minority thresholds needed to support an evaluation of impacts to environmental justice communities (https://www.epa.gov/sites/default/files/201608/documents/nepa_promising_practices_document_2016.pdf).

Only four of the tools reviewed provide support for an analysis of environmental justice effects suitable for an EA or EIS: the American Association of State Highway and Transportation Officials (AASHTO) Census Transportation Planning Products, the Census Bureau’s On the Map tool, and the New Jersey Department of Environmental Protection’s New Jersey Environmental Justice Mapping Tool. AASHTO’s tool and the Census’s tool can both be used to evaluate whether proposed transportation projects would disproportionately impact environmental justice communities based on travelers’ demographic characteristics and Census-reported commute patterns. The New Jersey Environmental Justice Mapping Tool is the only statewide tool identified that could be used to support community-level impacts (i.e., impacts to the environmental justice communities immediately adjacent to the project location). The North Central Texas Council of Governments Environmental Justice Index could be used to support an analysis at the MPO level.

The tools are strongest for their ability to identify environmental risks through project development, from initial scoping through an analysis of effects. Many of the tools would support an analysis of indirect and cumulative effects to equity communities as a result of climate change. For example, the recently updated