Uncovering physical activity trade-offs in transportation policy: A spatial agent-based model of Bogot��, Colombia.
Ivana Stankov, Jose D Meisel, Olga Lucia Sarmiento, Xavier Delcl��s-Ali��, Dario Hidalgo, Luis A Guzman, Daniel A Rodriguez, Ross A Hammond, Ana V Diez Roux
Author Information
Ivana Stankov: Urban Health Collaborative, Dornsife School of Public Health, Drexel University, 3600 Market St, 7th Floor, Philadelphia, PA, 19104, USA. is379@drexel.edu. ORCID
Jose D Meisel: Facultad de Ingenier��a, Universidad de Ibagu��, Carrera 22 Calle 67, 730001, Ibagu��, Colombia.
Olga Lucia Sarmiento: Department of Public Health, School of Medicine, Universidad de Los Andes, Bogot��, Colombia.
Xavier Delcl��s-Ali��: Research Group On Territorial Analysis and Tourism Studies (GRATET), Department of Geography, Facultat de Turisme I Geografia, Universitat Rovira I Virgili, C/ Joanot Martorell, 15, 43480, Vila-Seca, Spain.
Dario Hidalgo: Department of Industrial Engineering, Pontificia Universidad Javeriana, Bogot��, Colombia.
Luis A Guzman: Grupo de Sostenibilidad Urbana y Regional, SUR. Department of Civil and Environmental Engineering, Universidad de los Andes, Bogot��, Colombia.
Daniel A Rodriguez: Department of City and Regional Planning and Institute of Transportation Studies, University of California, Berkeley, 228 Bauer-Wurster Hall #1820, Berkeley, CA, 94720-1820, USA.
Ross A Hammond: The Brookings Institution, 1775 Massachusetts Avenue, N.W., Washington, DC, USA.
Ana V Diez Roux: Urban Health Collaborative, Dornsife School of Public Health, Drexel University, 3600 Market St, 7th Floor, Philadelphia, PA, 19104, USA.
BACKGROUND: Transportation policies can impact health outcomes while simultaneously promoting social equity and environmental sustainability. We developed an agent-based model (ABM) to simulate the impacts of fare subsidies and congestion taxes on commuter decision-making and travel patterns. We report effects on mode share, travel time and transport-related physical activity (PA), including the variability of effects by socioeconomic strata (SES), and the trade-offs that may need to be considered in the implementation of these policies in a context with high levels of necessity-based physical activity. METHODS: The ABM design was informed by local stakeholder engagement. The demographic and spatial characteristics of the in-silico city, and its residents, were informed by local surveys and empirical studies. We used ridership and travel time data from the 2019 Bogot�� Household Travel Survey to calibrate and validate the model by SES. We then explored the impacts of fare subsidy and congestion tax policy scenarios. RESULTS: Our model reproduced commuting patterns observed in Bogot��, including substantial necessity-based walking for transportation. At the city-level, congestion taxes fractionally reduced car use, including among mid-to-high SES groups but not among low SES commuters. Neither travel times nor physical activity levels were impacted at the city level or by SES. Comparatively, fare subsidies promoted city-level public transportation (PT) ridership, particularly under a 'free-fare' scenario, largely through reductions in walking trips. 'Free fare' policies also led to a large reduction in very long walking times and an overall reduction in the commuting-based attainment of physical activity guidelines. Differential effects were observed by SES, with free fares promoting PT ridership primarily among low-and-middle SES groups. These shifts to PT reduced median walking times among all SES groups, particularly low-SES groups. Moreover, the proportion of low-to-mid SES commuters meeting weekly physical activity recommendations decreased under the 'freefare' policy, with no change observed among high-SES groups. CONCLUSIONS: Transport policies can differentially impact SES-level disparities in necessity-based walking and travel times. Understanding these impacts is critical in shaping transportation policies that balance the dual aims of reducing SES-level disparities in travel time (and time poverty) and the promotion of choice-based physical activity.
