“In cities, it’s not far, but it takes long”: comparing estimated and replicated travel times to reach life-saving obstetric care in Lagos, Nigeria

Background Travel time to comprehensive emergency obstetric care (CEmOC) facilities in low-resource settings is commonly estimated using modelling approaches. Our objective was derive and compare estimates of travel reach CEmOC an African megacity models web-based platforms against actual replication travel. Methods We extracted data from patient files all 732 pregnant women who presented the four publicly owned tertiary Lagos, Nigeria, between August 2018 2019. For a systematically selected subsample 385, we their homes facility cost-friction surface approach, Open Source Routing Machine (OSRM) Google Maps, compared them by two independent drivers replicating women’s journeys. percentage reached within 60 120 min. Results The median for 385 OSRM Maps 5, 11 40 min, respectively. drive 50–52 mean errors were >45 min approach OSRM, 14 Maps. smallest differences replicated times seen night-time journeys at weekends; largest found weekdays above Modelled indicated that participants destination facility, yet journey showed only 57% were, 92% Conclusions Existing methods underestimate megacities. Significant gaps geographical access life-saving health services like must be urgently addressed, including urban areas. Leveraging tools generate ‘closer-to-reality’ will vital service planning if universal coverage targets are realised 2030.