Evaluating Equity: A Method for Analyzing Transit Accessibility of Affordable Housing Units

By Jing Guo, Candace Brakewood, Ashley Hightower & Christopher Cherry

Improving transit access for people in low-income communities is an important consideration for transit providers because many low-income populations who cannot afford a personal vehicle rely on public transit for their transportation needs. However, limited prior research has considered the transit accessibility of affordable housing units.

This study proposed a three-step method to evaluate transit equity of existing affordable housing units and potential modifications to local bus service to increase transit accessibility levels (assuming affordable housing locations do not change in the short term). The proposed approach was applied to three Tennessee cities with primarily bus-based transit systems: Nashville, Memphis, and Chattanooga. This paper holds particular relevance in Tennessee because the state's current Qualified Allocation Plan (QAP) for Low Income Housing Tax Credits does not incorporate transit access in the credit allocation process for affordable housing. This highlights the necessity of establishing a systematic evaluation method for policy-makers to assess the levels of transit accessibility at existing affordable housing units.

In the first step, the transit accessibility levels of affordable housing locations were measured using a web-based platform built on open-source software (Conveyal Analysis platform). Specifically, a cumulative opportunity measure was used to calculate the number of jobs reachable by fixed route transit service within 60-minutes from affordable housing locations. The affordable housing locations evaluated in this step included the three largest federally-administered affordable housing programs: Low Income Housing Tax Credits (LIHTC), subsidized Multifamily Housing properties, and Public Housing (PH).

Figure 1: Top five affordable housing locations with limited transit access in city of Memphis

The second step evaluated the transit equity of affordable housing considering two specific aspects: transit equity of existing affordable housing programs at the city level and transit equity of specific affordable housing locations within each city. The results of the city level analysis suggest that transit accessibility levels were distributed less equitably among affordable housing units than randomly selected housing units in Memphis; however, the opposite was true for Nashville and Chattanooga. These findings show that transit equity of affordable housing units can vary in different cities within a state. The second part of this step created an inequity index to rank specific affordable housing locations within each city. A higher inequity index indicated a higher demand (a higher number of affordable housing units) and a lower transit supply (a lower number of transit-accessible jobs). The result was a ranked list of affordable housing locations within each city, pinpointing specific sites where low-income residents may face challenges accessing job opportunities via transit (such as those shown in Figure 1 for Memphis). By doing so, we gained a deeper understanding of the locations that may require targeted interventions.

Figure 2: Overlapping isochrones before and after modifying the frequency of MATA transit route 40 for Wesley Highland Meadows

In the final step, we proposed modifications to local bus service that could be (relatively) easily implemented to improve transit accessibility levels for the specific locations identified in the previous step. This study demonstrated this process using Wesley Highland Meadows—an affordable housing location in Memphis—as an illustrative example. The results demonstrate a substantial increase in accessible jobs, rising from 135 to 6,400, after changing the headway of the closest transit route (Route 40) from 90 minutes to 60 minutes. The isochrones plot in Figure 2 shows that residents at Wesley Highland Meadows (the blue icon) can travel farther within an hour under the improved transit network (red isochrone). This underscores the potential effectiveness of implementing short-term transit service changes to improve accessibility of existing affordable housing locations.

In summary, by implementing this methodology, housing authorities and transit agencies can work towards creating more equitable and connected communities.

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Article Details
Evaluating Equity: A Method for Analyzing the Transit Accessibility of Affordable Housing Units
Jing Guo, Candace Brakewood, Ashley Hightower & Christopher Cherry
First published: July 20, 2023
DOI: 10.1177/03611981231182706
Transportation Research Record: Journal of the Transportation Research Board

About the Authors

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Dr. Christopher Cherry is a Professor of Civil and Environmental Engineering at the University of Tennessee, Knoxville. He has conducted emerging mobility research since the beginning of his graduate studies where he worked on one of the first map-based GIS transit itinerary planners. His subsequent work focused on micromobility, becoming a global leader in e-bike and shared micromobility research.

Ashley Hightower is a Graduate Teaching Assistant at the University of Tennessee, Knoxville where she is currently pursuing a Master’s degree in Civil and Environmental Engineering. Her research focuses on current issues in public transit such as equity, ridership recovery, and fare policy.

Dr. Candace Brakewood is an Associate Professor of Civil and Environmental Engineering at the University of Tennessee, Knoxville where she oversees a research group that focuses on public transit and shared mobility modes.

Jing Guo is a Ph.D. candidate in Transportation Engineering in the Department of Civil and Environmental Engineering at the University of Tennessee, Knoxville. Her research focuses on transit planning and transit equity analysis, aiming to evaluate and improve the transit accessibility for disadvantaged people who need public transportation in their daily life.