Methodological Evaluation and Adoption Rates of Transport Maintenance Depot Systems in Senegal: A Difference-in-Differences Analysis

{ "background": "Transport maintenance depots are critical infrastructure for ensuring road safety and vehicle fleet longevity in developing economies. However, systematic evaluations of the adoption and efficacy of modern depot management systems in sub-Saharan Africa are scarce, limiting evidence-based investment and policy.", "purpose and objectives": "This study aims to methodologically evaluate the implementation of modernised transport maintenance depot systems and quantify their adoption rates across the country. The primary objective is to isolate the causal effect of the new systems on operational performance metrics.", "methodology": "A quasi-experimental difference-in-differences (DiD) design was employed. Panel data from a sample of depots were analysed, comparing treatment units (modernised systems) with control units (legacy systems) over multiple periods. The core model is specified as $Y{it} = \\beta0 + \\beta1 \\text{Treat}i + \\beta2 \\text{Post}t + \\delta (\\text{Treat}i \\times \\text{Post}t) + \\epsilon_{it}$, where $\\delta$ is the DiD estimator. Inference is based on cluster-robust standard errors at the depot level.", "findings": "The adoption of modern systems led to a statistically significant 18.5% increase in mean vehicle availability, with a 95% confidence interval of [12.3%, 24.7%]. The analysis also revealed that depot size moderated this effect, with larger facilities showing greater relative gains in spare parts inventory turnover.", "conclusion": "The modernised depot systems demonstrably enhance operational performance. The DiD approach provides a robust methodological framework for evaluating infrastructure interventions in settings where randomised controlled trials are not feasible.", "recommendations": "Policymakers and engineering managers should prioritise the rollout of integrated depot systems, with tailored implementation support for smaller facilities. Future system designs should emphasise modular components to accommodate varying depot scales.", "key words": "infrastructure management, maintenance engineering, causal