This paper analyses some key decisions on transportation policy in the Nairobi metropolitan region (Kenya). It focuses on the majority of residents who do not own cars and are reliant on inadequate, often unsafe public transportation, walking, or riding bicycles to reach work and services. Building a public transportation system that offers more choice for the majority, in addition to making cities healthier, more accessible, and livable for all, is also critically important to challenging historically entrenched inequalities in access to urban space and opportunities. The paper examines four main, interrelated features of decisionmaking in Nairobi that impact how transportation projects and policies move forward, viz. the large and distorting role of external actors; fragmentation in institutions, policymaking and projects; closed and top-down planning processes; and the absence of mobilization for policies and projects that serve the majority of city residents, especially the poorer segments. Overall, these features have their roots in a broader political context which includes a historical legacy of planning as a form of exclusion, authoritarian politics, and institutional configurations and practices that favour patronage and rentseeking over progressive public policy. Bibliogr., notes, ref., sum. [ASC Leiden abstract]