An Assessment of Data, Tools, and Metrics for Equity in Decisions About Surface Transportation Investments (2025)
Chapter: 5 Vision, Recommendations, and Future Research Needs
5
Vision, Recommendations, and Future Research Needs
The study charge is to advise on ways to further the use of metrics to inform choices about surface transportation programs and projects that will advance equity. Specifically, the study committee is asked to identify, examine, and recommend equity metrics and analytical tools to test for guiding transportation program and project decisions that will lead to safer and more reliable access to critical destinations by disadvantaged and underserved populations.
In carrying out its charge, the committee consulted experts in housing, health, education, and safety, all of whom stressed the importance of transportation for providing access to destinations vital to enhancing individual and community quality of life. While it can be difficult to trace how a transportation investment contributes to longer-term positive outcomes for disadvantaged communities, it is imperative that transportation investments align with, and do not detract from, other policies and investments seeking such life improvements, for example, by creating more affordable housing, boosting economic mobility, and enhancing educational and health services. In this regard the use of metrics and analytical tools that reveal the equity effects of transportation in providing safe and reliable access to vital destinations can be paramount to furthering the broader societal goal of more equitable outcomes for disadvantaged and underserved populations.
In considering long-standing and emerging data, metrics, and tools available for assessing equity, the committee concluded that less emphasis should be placed on assessments that focus on the physical performance of transportation and more emphasis should be placed on how well transportation meets community needs. The committee observed that the physical
performance of infrastructure is regularly monitored and measured, whereas the performance of transportation investments in meeting the life needs of disadvantaged and underserved populations is seldom assessed. To recap the report’s logic and contents, Chapter 2 proposed a framework, based on causal chain analysis, for transportation practitioners to follow when defining equity metrics. Equity metrics currently in use were identified in Chapter 3 along with a range of attribute improvements for increasing the robustness and contextual suitability of the metrics.
Chapter 4 discussed newly emerging equity metrics and how these can be extended to different contexts, to different modes, and for different purposes, including advancing the state of practice used in assessments for environmental justice. The chapter highlights ways to better understand the problem of transportation insecurity, which provides a way to institutionalize long-term monitoring of how well new investments are helping to address the transportation needs of disadvantaged and underserved populations. Transportation insecurity results when individuals miss or forgo trips due to a lack of reliability or safety concerns. The metric can capture how changes in the underlying land use may modify transportation needs over time. It is only through engagement with disadvantaged and underserved communities that transportation insecurity can be understood. It is therefore critical for federal, state, and local governments and regional organizations to communicate directly with these populations as they begin to adopt and integrate equity and transportation insecurity measurements with other types of long-term performance measures.
Collectively, the recommendations that follow call for the institutionalization of currently available metrics, including the resourcing of emerging data, metrics, and analytical tools. Based on the study’s review of current practices, the committee is confident that it is both possible to integrate equity analysis into transportation investment decisions and that doing so is advisable to mitigate or reduce the challenges and barriers to safe and reliable access that disadvantaged populations face.
RECOMMENDATIONS
Pilot Test Equity Metrics for Accessibility and Environmental Justice
This report identifies a range of metrics that are being used today to evaluate equity for program and project decisions, including each metric’s data requirements. The metrics were identified from discussions with experts, including practitioners and researchers. The discussions revealed some metrics used for equity analysis that are aptly described as “proximity related.” Such a metric, for instance, may measure proximity to transportation infrastructure, such as an arterial highway or transit bus route, which may be treated as a
benefit or burden in the equity analysis. In the case of environmental justice, proximity metrics are used for assessing exposure to burdens, for instance, by indicating proximity to transportation sources of noise and air pollution. The discussions also revealed other commonly used metrics for equity analysis that are best described as “mobility” indicators, such as measures of travel time, congestion levels, or number of trips per day, which are calculated absent consideration of origin or destination or the location of infrastructure
Transportation agencies will often use proximity and mobility metrics for assessing equity because they are relatively easy to create. However, they share the deficiency of having little, if any, connection to accessibility outcomes that are the main purpose of transportation. Indeed, some proximity metrics may be misconstrued as indicators of access; for instance, by presuming that closeness to a highway ramp or rail transit station necessarily improves access to desired destinations. Mobility metrics have an even weaker association with accessibility outcomes. Measures of travel time or number of trips, for example, reveal little about the ability to reach specific destinations. Only when mobility is coupled with a destination (e.g., travel time to employment), such as in a travel demand model, can such measures provide an indication of accessibility.
The committee is in consensus that the preferred accessibility indicator for evaluating and prioritizing investment decisions is proximity to destinations. As described in Chapter 4, proximity-to-destination indicators are well established in the research literature and are being introduced into practice. The two forms that are predominant are cumulative opportunity indicators and travel-time opportunity indicators. The former count the number of destination types, such as job opportunities and health care facilities, that can be accessed from a specific location within a travel-time threshold for a specific transportation mode. The count, for example, may be of the number of jobs that can be reached from a census block location when driving or riding transit for 45 minutes or less. The latter metric calculates the travel time to a given, desirable location when using a range of available modes, such as the driving and transit travel time from a census block to a specified hospital or grocery store. These metrics should be incorporated into a continuous planning process that includes periodic updates to land use information describing the current location of destinations and means of reaching them. Similarly, in forecasting applications, future land use changes in addition to transportation system investments should also be considered to accurately reflect the expected change in proximity to destinations.
The report points to several states and metropolitan planning organizations (MPOs) that are using accessibility metrics for assessing the equity in transportation investments; albeit limited in the types of destinations covered. In many cases, they are using granular data about the location of housing, education, employment centers, and other land use types and
about the modal transportation networks that can connect residents to these destinations. When combined with demographic information on who is residing in the housing or using the different modes, the practitioner can analyze for disparities in access as experienced by populations of concern. The metrics can be used for both transportation investment and land use decision making. The efforts by these states and MPOs to develop what can be described as “proximity to opportunity” metrics provide a good starting point for further assessment and development.
It is important to emphasize that even as the committee favors a focus on accessibility in equity metrics, it also believes that more can be done to ensure equity in the distribution of transportation-related burdens through more consistent and regular environmental justice evaluations. Environmental justice evaluations are usually conducted for specific projects or plans. These evaluations measure the burden based on a proximity-to-investment metric—in other words, who is burdened at what distance from a transportation investment. Environmental justice analyses would be strengthened by a consistent practice of combining demographic information with geographic data, such as on highway crash fatalities and motor vehicle emissions, to make burden assessments and measure equity.
RECOMMENDATION 1: The U.S. Department of Transportation and Congress should direct, and resource as needed, states, localities, regional planning organizations, and other recipients of federal surface transportation funds to pilot the use of equity metrics to inform transportation prioritization and investment decisions. The pilots should include equity metrics for access to destinations, and environmental justice, defined to include health, safety, and environmental burdens.
Pilot Test Measurement of Transportation Insecurity
The concept of measuring a person’s transportation insecurity has emerged from research on people living with poverty and facing food insecurity due to a lack of resources and options for obtaining safe and nutritious food. The U.S. Department of Agriculture (USDA) defines households as being food insecure and has an index of four gradations of insecurity, from least to most severe. Likewise, transportation insecurity denotes a lack of reliable and safe transportation options. People who are transportation insecure miss trips and skip essential activities, contributing to social and emotional isolation. They may rely on others for rides or be forced to accept unsafe travel, such as using an isolated and unsheltered bus stop at night or walking along busy roads without sidewalks.
As discussed in Chapter 4, few tools and metrics are available to identify individuals who face transportation insecurity and for whom
the transportation system is failing to meet their needs. A good example of a transportation insecurity measurement tool is the Transportation Security Index (TSI) developed by researchers at the University of Michigan. Modeled after USDA’s food security index, the TSI is administered as 16-question and 6-question surveys, both of which have been validated using nationally representative surveys. Respondents are assigned a score representing their level of transportation insecurity, and they may be identified as experiencing no insecurity or insecurity that is marginal, low, moderate, or high. In this way, the TSI can complement other equity metrics, such as accessibility indicators, by revealing a person’s actual lived experience.
An advantage of such an index that is designed to capture the experiences of people living with transportation insecurity is that transportation planners can identify areas with concentrations of people experiencing insecurity, provided that the survey is administered over a large enough population and geographic scope. A single index also has the advantage of implementation simplicity for jurisdictions evaluating and prioritizing their transportation investment strategies. Changes in the index over time and by location can be monitored to assess progress and enable more refined corridor planning. Trends and patterns as indicated by the index can help policymakers at the state and federal levels gain a better understanding of how jurisdictions, as well as their own policies, are meeting the transportation needs of the disadvantaged. Although an index such as the TSI is a broad metric derived from a standardized set of questions, it provides a unique bottom-up approach that considers local conditions and needs to create an individual-level outcome metric that addresses limitations of existing approaches described in Chapter 3.
Transportation insecurity is a relatively new concept, and indexes that can readily capture representative levels of insecurity hold considerable promise for use in equity analysis to inform transportation decision making. However, more work needs to be done to test and validate indices of transportation security, such as the University of Michigan’s TSI. For instance, testing is needed to determine the optimal form for scaled use by the federal, state, and regional governments and for coupling the index with other metrics of accessibility to better understand the relationship between need and access.
RECOMMENDATION 2: The U.S. Department of Transportation and Congress should provide resources to states, local jurisdictions, regional planning organizations, and other recipients of federal surface transportation funds to pilot test tools that directly measure transportation insecurity as it is experienced and related by people. The pilot should be designed to demonstrate how tools measuring transportation insecurity relate to other equity metrics, such as access to essential destinations.
Fund and Support the Widespread Use of Equity Metrics
States, localities, and MPOs are likely to require added resources to fully integrate equity metrics into their transportation investment planning and prioritization processes. Many of the metrics for measuring access can be derived from travel models already in use. This report discusses the U.S. Department of Transportation’s (USDOT’s) Equitable Transportation Community Explorer initiative, the University of Minnesota’s Accessibility Observatory, and other initiatives that are making proximity-to-destination indicators more widely available for more destination types. An advantage of such metrics is that they can be integrated into the travel demand models that are already being used for transportation planning. The integration strengthens modeling by giving practitioners the ability to forecast the equity effects of planned transportation system improvements and other interventions.
Nevertheless, some states, local jurisdictions, and MPOs will need additional staffing capacity and staff training to use opportunity metrics. Lower-resourced agencies, in particular, will need assistance in establishing a new way to prioritize transportation projects and programs They will need resources, for instance, to better engage with disadvantaged communities. Some may need resources, training, or publicly available software tools for automating calculation of opportunity indicators by demographic group and by mode. The need for resources is especially acute for measuring transportation insecurity due to the need for surveys or other qualitative methods targeted to the most disadvantaged.
Recommendation 3: The U.S. Department of Transportation and Congress should provide resources for states, local jurisdictions, regional planning organizations, and other recipients of federal surface transportation aid to measure access, transportation insecurity, and environmental justice outcomes of their transportation investments and plans using the metrics and tools that were successfully piloted.
Advance Research on Transportation’s Role in Societal Outcomes
As documented in this report, transportation is critical to the economic and social well-being of people and communities. A growing body of research shows that the health, education, employment, and wealth generation outcomes of disadvantaged populations in particular are affected by transportation. While this research base has supported the development of more insightful and useful metrics and tools for assessing equity and transportation, an even deeper understanding of the causal connections is needed to inform the planning and prioritization of transportation investments.
In this endeavor, transportation can learn from other fields that use evidence-based research to guide practice. Notably, causal chain analysis is a logic model approach that is used in health and safety research, as well as in other fields, to help identify root causes and the many layers of contributors to an identified need or desired outcome. This report explains how causal chain analysis is being used to analyze vehicle crashes involving pedestrians and other vulnerable road users by researchers and practitioners who have increasingly adopted a safe systems approach to traffic safety. A concentration of pedestrian–vehicle crashes at an intersection that is revealed by a crash severity metric, for instance, might suggest that the intersection’s design is faulty, but a causal chain analysis that digs deeper may reveal even more fundamental problems. The intersection may be located in an area, for instance, where there is need for residents to walk at night. Stepping back even further, the causal chain analysis may reveal that land use and zoning policies that encourage a strict separation of residential locations from shopping and work location may be favoring driving while causing impediments to pedestrians, including safety hazards. Only by working through such causal pathways can new and innovative solutions be identified from the varied perspectives of urban planners, engineers, and community members.
While proximate causes can be easier to identify, transportation practitioners have a responsibility to measure how their investments affect lived experiences and contribute to quality of life. To do so, however, they will need to draw from a richer and more insightful knowledge base for understanding the causal relationship between their transportation decisions and the well-being of the people and communities served. One would expect this knowledge base to include, for instance, individual-level longitudinal research, qualitative research, and evaluation research that uses randomized controlled trials when feasible. Over time, such studies will add to and refine the base of knowledge about causal pathways and the multiple influences that can affect positive societal outcomes. In having a stronger understanding of how different factors, including transportation, affect positive societal outcomes, the practitioner will be in a better position to select the most appropriate indicators and metrics for equity analysis as practice evolves. Moreover, as knowledge accumulates about how different dimensions of the built environment influence societal outcomes, the range of solutions considered for addressing transportation needs and barriers is likely to expand beyond transportation investments and may include a mix of other types of transportation-related interventions (e.g., fare changes) and nontransportation solutions.
RECOMMENDATION 4: The U.S. Department of Transportation should fund sustained research to strengthen and expand understanding of existing, new, and emerging causal pathways from transportation investment to societal outcomes of critical importance.
IMPLEMENTATION CONSIDERATIONS FOR AMERICAN INDIAN/ALASKA NATIVE PEOPLES AND TRIBAL GOVERNMENTS
Equity indicators and metrics for surface transportation projects and programs affecting tribal lands and American Indian/Alaska Native (AI/AN) peoples require special attention. Federally recognized AI Tribes or AN entities have a complex relationship with the federal government that is defined by both dependency and sovereignty. Tribal lands present a complicated mix of land ownership and designation statuses that affect decision-making processes about infrastructure on tribal lands.1 In addition, the majority of AI/AN individuals live outside of tribal lands or territory for various reasons, including relocation programs2 and individual choices, driven in part by transportation insecurity and limited access to housing, employment, education, and health care. Thus, while tribal governments have their own need for equity-related data, metrics, and tools to inform their own transportation decisions, federal, state, and local governments also need better data, metrics, and tools for assessing the equity outcomes of their transportation decisions on tribal governments and AI/AN peoples living outside tribal lands.3
Federal, state, and local governments also need tools for assessing equity outcomes of their transportation programs and projects within tribal lands. Whereas the Bureau of Indian Affairs (BIA) and many Tribal Nations build and maintain roads on tribal lands, the majority of these roads are owned and operated by state and local authorities.4 In Okla-
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1 Congressional Research Service. October 14, 2021. “Tribal Lands: An Overview.” https://crsreports.congress.gov/product/pdf/IF/IF11944.
2 Public Law 959. https://www.govinfo.gov/content/pkg/STATUTE-70/pdf/STATUTE-70-Pg986.pdf; also known as the Indian Relocation Act of 1956. https://www.archives.gov/research/native-americans/bia/urban-relocation.
3 Due to their location, Alaska Native (AN) communities can require types of transportation that may not mirror those of the lower 48 states, such as ice roads and boardwalks. However, for the purposes of federal surface transportation and transit funding programs, AN communities are treated the same as those in the lower 48 states. For example, they are eligible to apply for and have been awarded discretionary grants for transportation projects under the Bipartisan Infrastructure Law. In addition, while Alaskan tribes generally are not recognized as having sovereign rights over territory and the sovereign rights of Alaskan tribes over territory continues to be litigated (e.g., https://alaskabeacon.com/2024/03/15/new-department-of-interior-opinion-promises-to-expand-tribal-jurisdiction-in-alaska), both Alaska tribes and tribes in the lower 48 states, which have territory rights must apply to the U.S. Department of the Interior’s Bureau of Indian Affairs to obtain right-of-way for their development projects (https://www.bia.gov/service/rights-of-way-individually-owned-indian-and-tribal-lands/apply-right-of-way).
4 25 CFR § 170.5 defines a Tribal Transportation Facility as “a public highway, road, bridge, trail, transit system, or other approved facility that is located on or provides access to Tribal land and appears on the NTTFI described in 23 U.S.C. 202(b)(1).” According to the National Tribal Transportation Facility Inventory (NTTFI), states and counties own 101,000 miles out of the total 157,000 miles of roadway (Bureau of Indian Affairs. “Operation and Maintenance.” https://www.bia.gov/bia/ois/division-transportation/operations).
homa, for example, all highways that traverse and provide access to tribal lands are owned and maintained by the state or counties.5 The Council on Environmental Quality’s (CEQ’s) Climate and Economic Justice Screening Tool (CEJST), the U.S. Environmental Protection Agency’s EJScreen, and USDOT’s Equitable Transportation Community (ETC) Explorer, which are the most prominent federal equity mapping tools, are of limited use to tribal governments, states, and MPOs attempting to use these tools for determining the location of their projects or planning areas in relation to AI/AN populations. For tribal lands, the problem is that the tribal census tracts used by the Census Bureau to define tribal lands do not always align with census tracts used in these tools. Indeed, only one of the three tools, the CEJST, references and maps tribal lands. Even so, this tool does not convey important local conditions in a tribal land. For instance, land within the boundaries of a federally recognized tribe may contain municipalities that span a range of income levels, but the entire mapped area is designated as disadvantaged.
Within the scope of this study, it was not possible to undertake a comprehensive assessment of data access and quality for tribal communities and AI/AN peoples. However, as a general matter, tribes struggle to access data, and they specifically lack access to high-resolution community, transportation infrastructure, and traffic engineering data. If they are to develop metrics for assessing the equity outcomes of their transportation investments, they will need assistance in obtaining the required data and developing the capacity to use those data. Tribes have some of the same constraints on their capacity for equity analysis as other governing bodies, but some of their constraints are distinct and arise from the structures for federal transportation programming and funding for tribes. By law, the Tribal Transportation Program (TTP) is jointly administered by the USDOT Federal Highway Administration (FHWA) and the U.S. Department of the Interior’s BIA.6 TTP is funded by the Highway Trust Fund and part of the Federal-Aid Highway Program. Depending on their capacity, as determined by FHWA, to administer a transportation program, tribes can enter into contracts or agreements with either FHWA or BIA to perform transportation activities authorized in the TTP. Tribes typically submit a
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5 This mixed ownership environment impacts the ability of tribal governments to address transportation insecurity, and road right-of-way ownership in this context is a significant challenge in general for tribal land infrastructure planning and management.
6 25 CFR § 170.5; co-administration was once guided by a stewardship plan last revised in 1996 (Testimony of John Baxter, 2011, U.S. Department of Transportation, https://www.transportation.gov/testimony/tribal-transportation-paving-way-jobs-infrastructure-and-safety-native-communities). Since 2016, federal regulations provide for a National Business Plan for stewardship of the TTP, but the plan is not completed (25 CFR Subpart F and 25 CFR § 170.700).
Transportation Improvement Plan (TIP) to the TTP at BIA. The FHWA Office of Tribal Transportation reviews applications and distributes funds to individual tribes based on a statutory formula. The portion of funds a tribe receives is known as the “tribal share.” Federal funds set aside for transportation planning are the typical funding source for activities such as tracking or analyzing equity indicators and metrics. The 2% set-aside for TTP funding mirrored the percentage provided for State Planning and Research (SPR), but this 2% was set aside from a smaller funding source that had to be divided among over 10 times more governments.7 To enhance capacity for equity-related planning and data support activities, tribal governments could use federal dollars eligible for transportation infrastructure projects. Diverting funding from needed transportation projects would be a difficult decision, and tribal governments have less room to maneuver than state DOTs.8
Of the total federal road and bridge funding provided to tribal governments in the 2021 Infrastructure Investment and Jobs Act (IIJA), 71% are formula funds. The remainder is from competitive tribal funding programs for specific projects, which have less flexibility for use than formula funds.9 The growing number of USDOT competitive grants are open to tribal governments, but the programs require tribal governments to compete against states and local governments. The capacity of tribes to compete, and, if
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7 In fiscal year 2024, the planning set-aside for the TPP was about $10 million. Spread across 574 federally recognized tribes, the Navajo Nation’s annual set-aside, the largest such allocation, is $1.3 million. For another 14 tribes, planning funds range from $100,000 to $400,000 annually, but the planning set-asides for many tribes are less than $20,000 annually (FHWA. “Tribal Shares and Special Appropriations for FY24 Full Year.” https://highways.dot.gov/sites/fhwa.dot.gov/files/Tribal%20Shares%20for%20FY24%20Full%20Year_0.pdf). Even for the Navajo Nation, this funding falls short of what is available to state DOTs. For a rough comparison, the state of Wyoming’s federal SPR funding for fiscal year 2024 was $6.6 million, or $11.50 per capita and $68.34 per square mile of land area. The Navajo Nation’s planning funds come to $7.27 per capita and $49.30 per square mile of land area (FHWA. “Table 13: Summary of Apportionments Authorized for Fiscal Year (FY) 2024” modified January 25, 2024, https://www.fhwa.dot.gov/bipartisan-infrastructure-law/comptables/table13p4.cfm; U.S. Census Bureau. “Wyoming.” https://data.census.gov/profile/Wyoming?g=040XX00US56. Accessed September 24, 2024; Navajo Nation. “History.” https://www.navajo-nsn.gov/History. Accessed September 24, 2024).
8 As another example of the potential effects of capacity constraints on decision making for equity, the fiscal year 2023 allocation for maintenance on BIA-owned roads was $39 million, while the backlog of deferred maintenance is around $400 million (U.S. Department of the Interior, President’s Budget Request for 2025, https://www.doi.gov/ocl/interior-budget-17). Operating under funding shortfalls, Tribal Nations are likely to prioritize projects based on criteria such as overall economic impact (which may lead to an interstate interchange for a large casino resort) rather than consider equity-related criteria (which may lead to addressing a structurally deficient bridge providing transportation to and from a rural community).
9 E.g., USDOT’s Tribal High Priority Projects (THPP) program.
successful, manage these funds separately from formula funds presents its own source of equity concern.10,11
In sum, the capacity of tribes to undertake equity analysis for transportation investment decision making is an important consideration that warrants assessment generally and with regard to specific tribal responsibilities, needs, and interests. An analysis of tribal transportation responsibilities and the resources minimally required to fulfill them would provide important baseline information for accurate assessments of equity in addressing transportation insecurity needs. While this report’s recommendations concerning equity metrics and tools for measuring access to destinations and transportation insecurity are applicable to tribes, the equity interests of tribal members, and the information needed for equity analyses, can differ from that of state and local transportation agencies. These interests may include, for instance, access to traditional hunting grounds and plant resources required to practice religious beliefs. Ensuring that measures encompass the particular life needs and interests of tribal members is therefore crucial for relevant assessments of transportation equity for tribal communities.
SUGGESTIONS FOR PENDING PILOT TESTING
The advice in this report is intended, in part, to inform follow-on pilot testing of promising equity metrics and analytic tools to evaluate how they can be successfully implemented for common and sustained use. Sponsored by USDOT, the pilot tests are slated to be conducted by the Transportation Research Board’s Cooperative Research Program (CRP) following the completion of this report. The purpose of the CRP work is to assess the potential for metrics and tools to be widely used. The committee believes that the pilot tests should be designed primarily for generalizability by evaluating metrics and tools that are sufficiently advanced and that are not conceptual or in early stages of development.
In considering candidates for the pilot testing, the committee concluded that the measurement of transportation insecurity to ascertain need
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10 National Academies of Sciences, Engineering, and Medicine. 2024. Elevating Equity in Transportation Decision Making: Recommendations for Federal Competitive Grant Programs. Washington, DC: The National Academies Press. https://doi.org/10.17226/27439.
11 Unlike state governments, tribal governments do not have the same authority to generate independent tax revenue to create and maintain the administrative proficiency and regulatory authority to carry out federal mandates or to provide matching funds. Legal barriers prevent tribes from exercising sovereign powers to tax activities within their reservation boundaries and generate general revenue streams that are free from federal restrictions or independent of federal funding formulas and programs (Huff, A. 2023. “Taxation in Indian Country: An Overview of the Causes of Tax Inequity in Indian Country and Modern Reform Efforts.” Center for Indian Country Development, Federal Reserve Bank of Minneapolis).
should be a priority. Understanding need is imperative and is critical for implementing other equity metrics. The University of Michigan’s TSI is an example of an advanced tool for measuring transportation need that has been validated and has the potential for widespread use. Its short-form design allows it to be readily incorporated into surveys, while its longer-form version could potentially support deeper geography-specific study in existing assessments (e.g., at the census-tract level) of transportation need. Significantly, pilot tests of a transportation insecurity metric such as the TSI could be designed to improve understanding of how proximity to destinations (i.e., accessibility) relates to needs and to transportation investments.
Finally, an important observation of this report is that the baseline transportation and access conditions of many tribal lands and AI/AN communities are not well understood, for instance, on road systems and travel patterns. Pilot tests of transportation insecurity metrics are critically needed for tribal lands and AI/AN communities and should be included in the follow-on research, but they must be coupled with efforts to measure and understand these baseline conditions.
