Nairobi Cannot Plan What It Cannot See: The Case for a Digital Twin of the City's Traffic and Mobility Network

This policy brief argues that Nairobi urgently needs a digital twin of its traffic and mobility network — an AI-driven virtual model capable of simulating road network behaviour and testing infrastructure interventions before they are built. With traffic congestion costing Kenya an estimated KSh 120 billion annually and the KSh 43.4 billion Clean BRT Line 3 (Chui) corridor moving into construction without a dynamic simulation model, the brief makes the case that evidence-based urban planning tools are no longer optional. It examines the data scarcity challenge unique to African cities, proposes a low-data modelling framework using mobile network aggregates, OpenStreetMap geometry, and matatu route records as proxy data sources, and sets out recommendations for the Government of Kenya, NaMATA, research institutions, and development partners. The brief is addressed to policymakers, urban planners, transport researchers, and scholarship and funding bodies investing in African smart city capacity.