Developing a Systems Dynamics Model of Road Safety in Nigeria: Feedback Loops, Leverage Points, and Policy Simulation

Road safety in Nigeria is a complex, dynamically structured problem in which the outcomes of interventions are shaped by feedback mechanisms, time delays, and non-linear system behaviours that conventional analytical approaches inadequately capture. This study develops a systems dynamics model of road safety in Nigeria to identify feedback loops, leverage points, and simulate the long-run effects of policy interventions. The research adopts a system dynamics methodology using the Vensim modelling environment, with model structure developed through causal loop diagramming workshops involving 50 road safety experts, transport economists, health professionals, and enforcement officers from across Nigeria's six geopolitical zones. Quantitative parameterisation draws on longitudinal accident data from the Federal Road Safety Corps (2000 to 2024), road expenditure records, fleet growth statistics, and healthcare system capacity data. The validated model captures six interacting subsystems: driver behaviour and licensing, vehicle fleet quality and maintenance, road infrastructure condition, emergency medical response, enforcement intensity, and public safety awareness. Simulation of 12 policy scenarios over a 20-year horizon reveals that enforcement intensity and emergency response capacity improvements generate the fastest safety returns, while road infrastructure investment has larger but slower-materialising effects with a seven to ten year delay in full impact realisation. A combination scenario achieving 50 percent fatality reduction requires simultaneous investment across at least four subsystems, demonstrating the inadequacy of single-intervention approaches. The study contributes a theoretically grounded, empirically validated systems model that advances road safety management science in Nigeria and provides a decision-support tool for the Federal Road Safety Corps and transport policymakers. Keywords: systems dynamics, road safety model, policy simulation, feedback loops, Nigeria.