Calculating Average Transit Times to Estimate Health Impacts in South Dallas

Purpose: Access to reliable transportation remains a significant social determinant of health, with far-reaching implications for employment, physical activity, food security, nutrition, and access to care. In Dallas, the National Equity Atlas estimates 1 in 10 households do not own a personal vehicle. These estimates worsen for households of color—nearly 1 in 5 Black households in Dallas lack a vehicle. The Baylor Scott & White Health & Wellness Center (BSWHWC) provides primary care and preventive health services for low-income, predominantly Black and Hispanic populations in South Dallas’s Frazier neighborhood. Over 1 in 4 residents in this neighborhood do not have access to a vehicle. Studies on barriers to healthcare access have cited lack of vehicle access and extended travel times as significant reasons for missed appointments and poorer health outcomes.

The Integrated Population Health Trial (I-POP) is designed to evaluate if Community Health Worker (CHW) navigation helps individuals improve their health compared to individuals receiving usual care at BSWHWC. CHW navigation involves monthly meetings with a CHW over 10 months, to connect participants to resources and utilize motivational interviewing to promote participant choices toward health improvement. Participants without a car are hypothesized to have longer public transit travel time and more absences for CHW appointments. This analysis identifies the extent and impact of transportation barriers for research participation in I-POP.

Methods: Adult participants living within 10 miles of the BSWHWC were recruited for I-POP through flyers at BSWHWC and community centers. Participants completed informed consent and baseline measures, then were randomly assigned to either the intervention (receiving CHW monthly navigation) or usual care. Participants were included in this study if they were assigned to the intervention and relied on public transportation. Twenty-five of 100 participants met inclusion criteria. Street addresses were batch-fed through a public transit directions application programming interface (API) to generate average amount of time spent traveling to the BSWHWC for monthly CHW sessions at any possible appointment times (Monday-Saturday, 8:00am-4:30pm). Session attendance followed a somewhat uniform distribution and average travel time was moderately right-skewed. However, deviations from normal could not be fixed through transformation due to small sample size. To examine the relationship between CHW appointment attendance and average travel duration, a linear regression model was run controlling for age, gender, race, and income level.

Results: Preliminary results indicate the average travel duration time for participants is not significantly related to participants’ attendance at CHW appointments (r=0.000534, p-value= 0.2390). Age and race showed minimal impact on session attendance, while being female showed a stronger positive association with session attendance (r=-2.90294, p-value=0.0591).

Conclusions: Participating in research interventions requires organizations to understand community barriers to attendance. While transportation is documented as a significant barrier in many studies, this small sample did not show a significant relationship between attendance and travel time using public transit. Further research is needed to examine this barrier with a larger sample, and evaluate other modifiable variables, like perceived benefits and overall satisfaction with study participation, that may increase participation at the BSWHWC.