Supporting public transit research in healthcare settings: Testing a free, fast, and secure method for routing public transit from patient address to the point of care

OBJECTIVES: Gaps in transportation, particularly public transit, are a significant barrier to accessible, high-quality healthcare. Health systems, payors, and regulatory bodies recognize the need to identify and address these gaps. However, clinical research examining public transportation accessibility and its impacts on healthcare utilization, outcomes, and costs remains limited. Existing tools used for studying public transit are generally non-HIPAA compliant, expensive, proprietary, and/or difficult to use. A tool addressing these concerns is needed to enable the incorporation of transportation variables into research and clinical care settings. 

MATERIALS AND METHODS: We developed and implemented a novel framework for building a public transit routing system that is comprised of free, publicly available data and offline software to maintain HIPAA compliance. The system consists of a transit router and a geocoder for converting addresses into coordinates. 

RESULTS: A total of 463 879 out of 505 379 (∼91.8%) of Baltimore, Maryland, addresses were successfully routed to University of Maryland Medical Center in 24 hours of compute time. A significant portion of journeys consisted of walking (36% of median trip time) or using a transit vehicle (57.2%). Testing the router with varying random-access memory levels showed a plateau in routing speed between 12 and 20 GB. The geocoding approach is >90% consistent with a widely used but non-HIPAA compliant geocoder. DISCUSSION: The methodology and step-by-step guidance shared in this study can allow researchers, public health professionals, non-for-profit agencies, and other stakeholders to efficiently, effectively, and safely incorporate public transportation information into their work. 

CONCLUSION: Public transportation routing using freely available data and software is possible in a HIPAA-compliant manner.