Traditionally, the maintenance and management of road geotechnical structures have been based predominantly on measures taken after regular inspections, a process called “post-maintenance”. However, there are growing efforts to reduce life cycle costs (LCC) by considering the preventive conservation of public structures. However, the deformation and degradation mechanisms of earthen structures are not fully understood, and no clear methodology for maintaining and managing them over time has been established. In this study, we propose a new approach and specific practical methods for preventive conservation of road geotechnical structures. Specifically, by considering practicality in actual operations, we propose the enhancement of regular inspections, optimization of LCC, and degradation prediction methods. Furthermore, we propose methods for evaluating the effectiveness of maintenance (life-extension measures), considering different environmental conditions, and the longevity (life prolongation) of structures through improved component performance.