Health and equity in transportation health impact assessments: A retrospective analysis

Introduction: The Infrastructure Investment and Jobs Act (Public Law 117-58) has ambitious intentions beyond roads and bridges including climate change mitigation and adaptation and environmental justice. As these projects are launched health and equity impacts should be evaluated. There are 14 documented pathways that connect transportation to health. Health Impact Assessment (HIA) can be a valuable tool in infrastructure planning to ensure that project benefits are maximized and harms minimized; but the practice of HIA with respect to coverage of the 14 pathways is unknown and its role in promoting equity is mixed. Approach: We conducted a retrospective review of US transportation HIAs to explore the role of health and equity in the practice of transportation planning aimed at identifying areas for growth. We examined: 1) the presence of and assessment methods for the 14 pathways; and 2) equity topics and assessment methods. Results: We reviewed 46 HIAs conducted between 2007 and 2020; 21 (47%) were county-level, 18 (38%) were city-level and 7 (16%) were state-level. The HIAs covered 8 of 14 pathways on average. We observed an equity “gap”; about 40% of the sample did not include equity recommendations. City HIAs had the smallest equity gap at 29%, followed by county HIAs at 38% and state HIAs at 43%. Several under-utilized pathways were identified, however, assessment methods exist for noise, contamination and heat assessments leaving greenhouse gases and electromagnetic fields as areas for development. Methods used to access equity were primarily literature reviews and demographic data analysis. Conclusions: For HIAs to enhance health and equity in robust transportation planning, we should prioritize developing tools and methods for assessing greenhouse gases and electromagnetic fields, and ensuring equity needs are evaluated through primary data collection.