Impact of Quito's first metro line on the accessibility to urban opportunities

One of the main challenges for cities is to provide equitable access to urban opportunities such as commerce, jobs, recreation, and other facilities and services. Several cities are planning and building mass public transport systems to overcome the accessibility gap derived from urban sprawl, spatial exclusion, and extreme land-use specialization. Nevertheless, there is no information on how these transportation projects will impact overall and relative accessibility for different population groups, especially those with current low accessibility. This study proposes a rigorous and replicable methodology to measure the impact of public transport projects on the overall accessibility and accessibility gap to urban opportunities for different socioeconomic groups. The methodology comprises three main phases: i) the characterization of accessibility to urban opportunities through public transport; ii) the measurement of the accessibility gap between socioeconomic groups, and iii) the impact of the metro's implementation on accessibility and the gap. All the procedures were implemented using open-source software and publicly available data, guaranteeing transparency and replicability. We applied this methodology to analyze the impact of implementing the First Metro Line (PLMQ) in Quito, Ecuador. The results show that the PLMQ will increase overall accessibility to urban opportunities, and this impact depends on travel time and current accessibility levels. The impact of the PLMQ on the accessibility gap will be more modest, and the benefits will be more important at long travel times. We argue that incorporating this kind of analysis on early planning phases of public transport projects will allow better planning and design decisions and inform public debate about significant investments in sustainable mobility.