Assessment of Deferred Maintenance Impacts on Flexible Pavements in Hawassa City and Countermeasure Strategies Using the HDM-4 Mode

Abstract

Highways are critical assets that play a vital role in a nation's socio-economic activities. Ensuring their effective and efficient maintenance is essential to sustaining the required level of service. However, the absence of proper and scheduled condition surveys, as well as delayed maintenance, leads to unnecessary costs and public inconvenience. This study examines the road maintenance management system of the Hawassa City Municipality Office with the objective of establishing an improved framework to mitigate issues arising from deferred maintenance. The research identifies various types of road damage and corresponding repair techniques that can help the city avoid excessive economic expenditures. The investigation reveals multiple surface pavement deteriorations along the study area’s road segments, including potholes, raveling, alligator (crocodile) cracking, and edge breakage. The study evaluates the impact of deferred maintenance on Hawassa’s flexible pavements by selecting highly deteriorated road sections based on key performance indicators and assessment criteria such as pavement condition surveys and traffic volume analysis. The research further examines the existing maintenance practices and management system, assesses the consequences of deferred maintenance, and recommends minimum maintenance strategies to prevent the need for costly rehabilitation or reconstruction, which poses a significant financial burden for Ethiopia. Data for this research were gathered using both primary and secondary sources, including interviews, visual analysis techniques such as photographic documentation, and examinations of international standards and manuals. The gathered data were examined through descriptive, exploratory, and HDM-4 models. Following the study's results, corrective actions were recommended for the Hawassa City Municipality Office. Additionally, the research assesses the economic consequences of poor maintenance using the Highway Development and Management model, which quantitatively analyses impacts by incorporating road network conditions, vehicle features, and maintenance schedules. The study emphasizes that effective maintenance considerably prolongs the lifespan of road infrastructure. Neglecting timely maintenance not only reduces service levels and accessibility but also leads to a substantial increase in the total lifetime cost of transport infrastructure. This in turn, negatively impacts the overall economic growth of the country. Therefore, road sections in the study area require reconstruction, and selecting an appropriate project case scenario is crucial for sustainable infrastructure management.