2026, Vol. 5, Issue 1, Part A

Small bridges constitute a significant portion of rural and secondary road networks worldwide. These bridges play a crucial role in ensuring local connectivity, economic activity, and access to essential services.

Small bridges constitute a significant proportion of rural and secondary road networks worldwide and play a crucial role in ensuring local connectivity, economic activity, and access to essential services. Despite their importance, these structures are often subjected to limited inspection budgets, infrequent assessments, and delayed maintenance interventions. Traditional bridge condition assessment has relied heavily on visual inspections supported by standardized rating systems, which, although practical, are inherently subjective and dependent on inspector expertise. In recent years, the growing need for rapid, low-cost, and scalable assessment techniques has driven the development of alternative methods that complement or partially replace conventional visual surveys. This review examines the evolution of rapid bridge condition assessment approaches for small bridges, tracing the transition from manual visual rating systems to technology-assisted and mobile imaging-based techniques. The paper synthesizes existing literature on visual inspection protocols, simplified condition indices, non-destructive evaluation tools, and emerging image-based methods using smartphones, unmanned aerial vehicles, and vehicle-mounted sensors. Particular emphasis is placed on the applicability of these methods in resource-constrained settings where full-scale structural health monitoring systems are impractical. The strengths, limitations, data requirements, and operational constraints of each approach are critically discussed. The review further highlights how mobile imaging and automated data processing can enhance consistency, reduce inspection time, and support evidence-based maintenance prioritization for small bridges. By consolidating current knowledge, this research aims to provide infrastructure managers, engineers, and researchers with a clear understanding of available rapid assessment methods and their potential integration into routine bridge management practices. The findings underscore the need for hybrid assessment frameworks that balance simplicity, reliability, and technological feasibility while addressing the unique challenges associated with small bridge networks.