Uncovering physical activity trade-offs in transportation policy: A spatial agent-based model of Bogotá, Colombia.

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 Bogotá 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 Bogotá, 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.

COVID-19 and public transport: an overview and recommendations applicable to Latin America / COVID-19 y transporte público: una revisión y recomendaciones aplicables a América Latina

Abstract The article presents a general overview on COVID-19 transmission in the context of public transport, particularly applicable to decision making in Latin America. Based on recent findings on COVID-19 transmission and the relative importance of each factor (droplets, fomites, and aerosol routes) in such transmission, we seek to update the discussion on the topic that has generally been based on social distance as the only parameter for reducing the risk of transmission and broadens the vision to integrate ventilation, users' behavior (mask and eye protection use, silence while in the transport system) and travel distance. Recommendations to improve mobility conditions reducing the risk of COVID-19 contagion are provided.

Resumen El artículo presenta una revisión de transmisión de COVID-19 en el contexto de transporte público, con aplicación particular para toma de decisiones en América Latina. Con base en los hallazgos recientes sobre transmisión de Covid-19 y la importancia relativa de cada factor (gotículas, fómites y rutas de aerosoles) en dicha transmisión, buscamos actualizar la discusión sobre el tema que generalmente se ha basado en la "distancia social" como parámetro único de reducción de riesgo de transmisión y amplía esta visión para integrar la ventilación, el comportamiento de usuarios (uso de mascarilla, protección ocular, silencio), y la distancia de viaje. Se indican al final recomendaciones para mejorar las condiciones de movilidad en general sin aumentar el riesgo de contagio de Covid-19.