"background": "Transport depot maintenance systems are critical for national infrastructure, yet their reliability in developing economies is under-studied. Existing evaluations often lack longitudinal rigour and robust statistical frameworks, leading to inefficient asset management and service delivery. ", "purpose and objectives": "This study aims to methodologically evaluate approaches for assessing transport depot system reliability and to implement a panel-data estimation model to quantify reliability trends and determinants within the Tanzanian context. ", "methodology": "A comparative study design was employed, analysing operational and maintenance data from a national sample of depots. The core analytical framework uses a fixed-effects panel regression model: Reliability{it = \ + \1 Ageit + \2 Budgetit + \3 Workforceit + \₈ₓ, where i denotes depot and t denotes time. Inference is based on cluster-robust standard errors to account for serial correlation. ", "findings": "The panel-data approach demonstrated superior explanatory power compared to cross-sectional methods. A key concrete result is that a 10% increase in preventative maintenance budget allocation was associated with a 4. 2 percentage point increase in system reliability (95% CI: 2. 1, 6. 3). Depots implementing standardised diagnostic protocols showed markedly more consistent performance. ", "conclusion": "The application of panel-data econometric techniques provides a more valid and reliable methodological foundation for engineering system assessment than traditional snapshot analyses, capturing unobserved heterogeneity and temporal dynamics. ", "recommendations": "Infrastructure agencies should adopt panel-data frameworks for systemic performance monitoring. Policy should prioritise ring-fenced funding for preventative maintenance and mandate the implementation of standardised operational protocols across all depot facilities. ", "key words": "system reliability, maintenance engineering, panel data, fixed-effects model, infrastructure management, transport depots", "contribution statement": "This paper provides a novel methodological application of panel-data econometrics to the longitudinal assessment of engineering system reliability in a
Mwakyembe et al. (Wed,) studied this question.