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Measuring access to opportunities to advance equity

Cutting-edge computation facilitates evaluation of equity in access to jobs, across millions of origins across Southern California

This year has seen new momentum for evaluating how transportation can advance both equity and access to opportunities. In the United States for example, over the course of a few months:

  • The US Department of Transportation (USDOT) publishes a Request for Information (RFI) on Transportation Equity Data. Methods for measuring access receive special attention.
  • TransitCenter releases its Equity Dashboard, with statistics and maps of how access compares across socioeconomic groups in six metropolitan regions.
  • The Transportation Research Board holds the inaugural Conference on Advancing Transportation Equity, including active participation from core Conveyal users and sessions on topics such as “Equity in Housing and Job Access.”

Are you interested in quantifying access to opportunities and progress toward equitable transportation systems in your region? Conveyal makes it easy with a purpose-built, innovative tool, as this blog series illustrates.

Why measure access to opportunities?

Urban passenger transportation’s fundamental purpose is connecting people to destinations that matter to them. Yet traditional guidance on quantifying equity has often missed the mark, focusing on narrower benefits, such as access to intermediate points (e.g. the nearest bus stop) rather than peoples’ true destinations. In the United States, policy related to federal civil rights laws (Title VI) endorses simplistic stop catchment-area demographic methods. As Zak Accuardi writes, official guidance from the US Federal Transit Administration (FTA) and Department of Justice…

includes criteria that can easily be applied in problematic ways that run counter to Title VI goals. The FTA allows agencies to use either census data (e.g., data about who lives near a changing route) or ridership data (i.e. demographic data about who uses a changing route) for Title VI analysis.

Instead of considering only who lives around stops or rides certain routes, improvements should be measured in terms of how they “improve access to opportunities for people of color and in low-income communities,” requiring practitioners to “go beyond baseline compliance with federal Title VI requirements.”

The application of access concepts at regional and national scales has become a mainstream possibility in recent years due to a surge in availability of transportation and demographic data, as well as the commercial availability of large-scale cloud computing. Practitioners increasingly recognize this possibility, as many responses to USDOT’s recent RFI show.

Screenshot of the top portion of a US government website titled Request for Information: Transportation Equity Data (https://www.regulations.gov/document/DOT-OST-2021-0056-0001)

Responses to USDOT RFI

In May 2021, USDOT released the aforementioned RFI on transportation equity data. One question area specifically covers access to opportunity indicators:

Transportation plays a critical role in how people access what they need (e.g., jobs, school, healthcare) and facilitates the movement of essential goods. What methodologies exist for measuring access to goods, services, education, recreation, and employment; well-being; and transportation reliability for people of color and other underserved groups?

As our full RFI comment notes, we are excited that USDOT seeks to advance transportation equity through new data and measurement approaches focused on access to opportunity measures.

Many other commenters, from advocacy groups, transit agencies, metropolitan planning organizations, and state departments of transportation, also shared perspectives on these measures. For example:

  • TransitCenter recommends supplementing “narrow analyses measuring the impact of proposed changes” under current guidance with standards for “the equity of a region’s existing transit network and whether that network offers more equitable access over time.”
  • King County Metro describes pitfalls of an ad-hoc workflow built from various tools to calculate access to opportunities. Because of laborious network editing and debugging, sparse spatial sampling, and computational limitations, access analysis took “2–4 days of analyst time” for each phase of their network redesign and ultimately “missed the mark on quantifying the benefits and disbenefits of the network change.” As we describe below, purpose-built tools are now available to address these challenges.
  • The Chicago Transit Authority expresses strong support for “the use of ‘access to opportunity’ metrics to evaluate transportation projects and their role in advancing equity” and encourages USDOT to account for “actual service and reliability” in these metrics.
  • The National Association of City Transportation Officials (NACTO) argues that instead of prioritizing vehicle speed and throughput, governments should “evaluate grant applications and prioritize investments based on how well potential projects connect people to jobs, education, and amenities.” NACTO also notes that “multiple tools already model project evaluation based on access, such as the State Smart Transportation Initiative’s Measuring Accessibility report
  • The Massachusetts Department of Transportation (MassDOT) states that multiple datasets and platforms now include accessibility indices and that “Each of these datasets has its own set of limitations and challenges, but we prefer to use Conveyal because it is user-friendly and easy to navigate.”

To reiterate key points from these comments, planners and transportation authorities should track the access enabled by baseline multimodal networks and how it evolves over time. To do so, they need rapid-turnaround, user-friendly tools that capture important aspects of peoples’ experience, such as variability in travel times.

Rapid detailed analysis of access to opportunities

Conveyal enables rapid, detailed analysis of access to opportunities, with a particular emphasis on public transit and active modes. Instead of taking 2–4 days to evaluate access from certain origins in a region, Conveyal returns results at much higher spatial and temporal resolutions across a region in 2–4 minutes, thanks to highly optimized routing software and cloud computation. Furthermore, the Conveyal team publishes this routing software under a permissive open-source license to promote transparency and reproducibility.

Based on the comments above, supporting access to opportunities indicators and noting the shortcomings of other tools, we believe Conveyal’s capabilities have an important role to play in emerging policy to advance transportation equity. A few examples show how leading agencies are leveraging these capabilities:

If you are interested in seeing these capabilities for yourself, please access our demo or get in touch.

Additional considerations

Upcoming blog posts in this series will expand on using Conveyal for equity analysis. Before jumping into the details, three additional considerations deserve mention.

First, consider equity of service given near-term demand. New Conveyal features make it easy to compute travel time matrices for large numbers of origin-destination pairs under different scenarios. These results can be paired with demand data, from on-board surveys or novel location-based services datasets such as StreetLight Data (which now offers a Conveyal integration), to assess disparities in travel time changes for different groups.

Second, consider actual operations and passenger experience, not just idealized schedules. Researchers have quantified discrepancies between scheduled, operated, and experienced travel times (e.g. in Toronto, San Francisco, Boston, Jacksonville, São Paulo, and Chicago), and proof-of-concept analyses in Conveyal have quantified transit reliability using access to opportunity indicators.

Finally, consider longer-term shifts in demand and actively mitigate displacement. Without policies to counteract gentrification and displacement, investments in previously underserved communities may end up pricing out the populations they purport to serve. We recognize that affordable housing programs, community land trusts, and other policy interventions are not our expertise, and we would welcome additional research and community collaborations on these topics. We have appreciated past opportunities to help integrate our software with other models that better account for changing land use and individual behavior, and we know that working with a wide range of academic and community experts is vital to ensure that the software we build helps meaningfully advance equity in practice.

Screenshot of the Conveyal user interface, including a map with dot density layer for workers in Southern California and a blue polygon boundary for the City of Los Angeles, as well as a histogram of the distribution of access to jobs
Detailed distribution of access to jobs in Los Angeles

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We enable people and institutions to make smarter decisions by applying technical expertise in open source software and open data to create improved transportation systems, more livable cities, and a better world.

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Anson Stewart

Anson Stewart

Analysis and Research, @conveyal | PhD in Transportation, @MIT | '10 TJ Watson Fellow + @SwatAlum | Californian in exile on East Coast

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