Building Adaptive Capacity to Respond to Extreme Heat among Bus Riders in Tennessee: A Mixed Method Study

As climate change accelerates, extreme heat poses growing public health risks, particularly for transit-dependent populations who may face disproportionate exposure due to regular transit use. This mixed-methods dissertation investigates the intersection of extreme heat, public transportation, and social vulnerability through three studies: a systematic literature review, a statewide survey, and a qualitative interview study in a Southern U.S. city. The study is framed by the concept of environmental justice, grounded in Title VI of the Civil Rights Act of 1964, which mandates that individuals not be excluded from or discriminated against in any program receiving federal funding. Chapter I uses systematic scoping review methodology to synthesize findings from 15 peer-reviewed studies (1990–2024) on public transit and extreme heat. Five key themes emerged: (1) the intersection of weather, transit, and social vulnerability; (2) health and safety impacts of heat exposure; (3) thermal comfort in transit environments; (4) coping behaviors and adaptation strategies; and (5) innovative cooling and infrastructure solutions. The review reveals research gaps, particularly around the lived experiences of marginalized riders and the need for interdisciplinary, equity-focused inquiry. Chapter II presents findings from a statewide survey of 355 bus riders in Tennessee, analyzed using multiple regression techniques guided by the Extreme Heat Vulnerability Framework. Results show that access to real-time transit apps and weather alerts are the strongest predictors of adaptive capacity—measured through knowledge, attitudes, and practices (KAP). Paradoxically, higher KAP scores were associated with increased reports of heatrelated symptoms, suggesting that awareness may heighten recognition of illness. Key vii indicators of vulnerability included employment, disability, medication use, and digital access. Chapter III, guided by the Social Determinants of Health and Transport-Related Social Exclusion frameworks, draws on in-depth interviews with eight Knoxville riders. Five themes emerged, including the physical and emotional toll of commuting in heat and the absence of cooling infrastructure. Together, these studies underscore the need for justice-centered, climate-resilient transit systems that prioritize the needs of vulnerable riders through equitable infrastructure, accessible communication, and inclusive urban planning