Sensitivities of weighting methods in the sustainability assessment of public transport in Latin American cities

Abstract

Several studies have been conducted on the sustainability performance of public transport (PT) systems, but few of these studies have focused on Latin American cities, which present a number of distinctive characteristics. These include the prevalence of harassment against women in PT vehicles, the use of outdated technology, and the lack of data availability. This study presents a sensitivity analysis for the Sustainable Public Transport Index for LATin AMerica (SPTI-LATAM) for 11 Latin American case study cities. Four weighting methods are applied at the levels of sustainability dimensions, categories and indicators, including the Equal Weighting Average (EWA), Analytic Hierarchical Processes (AHP), and Budget Allocation Points (BAP) approaches. Monte Carlo simulations are added to examine the robustness of the SPTI-LATAM city rankings for a large number of randomly drawn weights. Local stakeholder preferences in AHP and BAP, sensitivities in PT sustainability performance and ranking positions of the 11 cities are presented as the main results. The study’s findings reveal substantial differences between the stakeholder preferences and the EWA approach. The highest weights are assigned to the System Effectiveness and the Social dimensions. Ranking positions are stable for cities with the highest sustainability performance, whereas those with lower performance are show greater sensitivity, which is related to a less balanced scoring of single indicators. Recommendations are made for the further development of the SPTI-LATAM into a tool that measures the sustainability performance of PT systems in the Latin American context reliably across cities and over time, while also representing local stakeholders’ preferences.