One of the goals of school choice is to allow parents to send their children to higher-performing schools. Several studies have shown that distance to school is one of the main determinants of school choice, but challenges to address endogeneity issues remain. To address these concerns, in this paper I take advantage of the construction of a new subway line in Santiago, Chile, that crosses a large area of the city previously unconnected to the subway network. I provide convincing evidence to show that the introduction of the subway line was arguably exogenous for families living close to the new subway stations. With rich administrative data, which includes all high-school seniors that registered to take a national university entrance exam, I use a repeated cross-section difference-in-differences analysis and find that (i) students near the new subway stations travel significantly farther to school than students who live in nearby areas with no subway stations, and (ii) that students near the subway are willing to travel slightly farther to attend schools that perform better in standardized tests, although this effect is small and only significant for language test scores. This set of results is particularly informative in the context of the broader school-choice debate, contributing causal evidence on the effects of transit access on school-choice.