Randomised Field Trial for the Risk Reduction and Reliability Optimisation of Transport Maintenance Depots in Senegal

"background": "Transport maintenance depots are critical infrastructure for road network reliability, yet systematic evaluations of their operational risk and reliability in West Africa are scarce. Existing assessments often lack rigorous, field-based methodologies to quantify the impact of targeted interventions. ", "purpose and objectives": "This study aimed to develop and apply a randomised field trial methodology to empirically measure risk reduction and optimise the reliability of transport maintenance depot systems. ", "methodology": "A randomised controlled trial was conducted across a representative sample of depots. Depots were randomly assigned to an intervention group, receiving a standardised package of procedural and physical upgrades, or a control group. Primary outcomes were measured using a composite reliability index (CRI). The treatment effect was estimated using a linear mixed model: CRI{it = \0 + \1 Treatmenti + \ Xit + ui +, where ui denotes depot random effects. Robust standard errors were clustered at the depot level. ", "findings": "The intervention yielded a statistically significant mean improvement in the CRI of 0. 42 points (95% CI: 0. 28 to 0. 56, p<0. 01) compared to control depots. A key theme from ancillary data was the pronounced effect on spare parts inventory reliability, which showed the largest component-wise gain. ", "conclusion": "The randomised trial confirms that structured, low-cost interventions can substantially enhance depot system reliability and reduce operational risk. The methodology provides a robust framework for evidence-based infrastructure management. ", "recommendations": "Infrastructure agencies should adopt randomised field evaluations to prioritise maintenance investments. The implemented intervention package should be considered for broader rollout, with particular attention to inventory management systems. ", "key words": "reliability engineering, infrastructure management, randomised controlled trial, maintenance optimisation, risk assessment", "contribution statement": "This paper provides the first application of a randomised field trial to evaluate engineering interventions for transport depots in the region