Integration of Landslide Susceptibility and Road Infrastructure Vulnerability for Risk Assessment and Mountain Road Resilience Enhancement

Roadways are the most common mode of transport because they offer last-mile connectivity and are user friendly. In hilly and mountainous regions, however, most roads are vulnerable to landslides, posing significant disruption in traffic movement as well as risk to human life and property. Understanding these road vulnerabilities is important for ensuring the smooth operation and safety of transportation service. This paper aims to explore the risk of landslides to road and road infrastructure along the Narayanghat-Kathmandu road section in Nepal, and for this, we have taken into account 11 landslide conditioning factors and created a landslide susceptibility map of the study area, employing the analytical hierarchy process (AHP) in the geographic information system (GIS) platform. The performance of the susceptibility model was evaluated by area under the receiver operating characteristic (ROC) technique using 122 historical landslide inventory datasets. Subsequently, considering seven critical road infrastructure elements at risk, landslide vulnerability map was prepared for the target roadway. By combining susceptibility and vulnerability maps, a disaster risk map was generated. From the obtained results, it was understood that several key components of the road infrastructure in the study area are located at high-risk zone, which include four bridges, thirty two culverts, thirty two retaining walls, twelve safety blocks, and two delineators. The significance of this study is at mitigating the adverse impacts of landslides on roadway infrastructure and improving the safety and reliability of transportation network in mountainous regions.