Socio-spatial concerns are gaining increasing attention in the design of interventions for urban mobility. This is especially true in contexts traditionally characterized by structural inequality and high levels of poverty, in which transport can be a decisive contributor to development thanks to its contribution to a higher social inclusion. Amongst them, Latin America has emerged as a significant laboratory for urban and transport policy due not only to its socioeconomic conditions but also to the implementation of different mobility strategies based on the construction of traditional and innovative infrastructures such as subways and bus rapid transit (BRT) systems. These two transport systems can be complementary or alternative to each other: this depends not only on their transport capacity, their economic sustainability, and to their levels of public acceptability but also on social, political, and spatial features of the setting they serve. This paper intends to discuss the socio-spatial consequences that interventions based on different transport systems can generate, examining them in the city of Quito, Ecuador. The discussion is based on the implementation of the existing BRT network and of a subway line under construction. Reconstructing two contrasting transport policies developed in the city in the last 25 years, this paper proposes an overview of the socio-spatial concerns that influenced and were influenced by urban mobility planning in Quito. To do so, this paper reviews and compares the socio-spatial concerns related to BRT and subway corridors, considering their accessibility, the wider urban transformations they promote, their economic sustainability, and the overall public acceptability, estimating to what extent these have influenced the decision to implement a certain transport policy.