Assessing the health impacts of changes in active transport: An updated systematic review

Background: Modelling studies consistently demonstrated significant health impacts resulting from shifts to active transport, such as walking and cycling, compared to other modes. However, limited understanding of diverse modelling approaches hinders the effectiveness of existing models in advancing future endeavours. Our study aims to compile modelling approaches, settings, and scenarios used in transport health impact modelling and assess the extent to which studies have quantified differential and equity impacts of transport mode shifts.Methods: Following 2020 PRISMA guidelines, we systematically reviewed six databases: Ovid Medline, Ovid Embase, Scopus, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and Transportation Research International Documentation. Search terms included transport modes, health outcomes, and assessment methodologies. The search covered articles published from 2014 onwards to minimize overlap with previous reviews. Two independent researchers screened records, resolving discrepancies by consensus.Results: We identified 24,494 records and included 87 after full-text screening. Studies spanned 28 countries, with five having five or more exclusively focused studies: USA (n = 22), Australia (n = 10), UK (n = 6), Ireland (n = 5), and New Zealand (n = 5). Only 12 studies assessed low- or middle-income countries (China, India, Malaysia, Mauritius, Iran, and Brazil). Comparative risk assessment was the most used approach (n = 51), with Integrated Transport Health Impact Model (ITHIM) (n = 17) and World Health Organization HEAT Tool (n = 11) as popular tools. Scenarios covered hypothetical and observed travel patterns in diverse populations. Less than one-third of studies estimated impacts on population subgroups.Conclusion: Multiple transport health impact models have been applied globally, adapting to various settings and environments. However, significant gaps remain in quantifying differential and equity impacts of transport scenarios across population groups, a critical priority due to prevalent health and transport inequities. Future modelling should capture the full range of health pathways associated with transport to enhance its utility in informing decision-making processes.