This research investigates the causes of significant road subsidence observed on Lettu Karim Kadir Street, Gandus District, Palembang City, starting in early 2025. The study addresses the urgent need to identify the technical factors contributing to this subsidence, which has disrupted traffic and indicates potential geotechnical issues in the road's subgrade. The research methodology involves analyzing the mechanical properties of the soil through laboratory testing, including Proctor Standard compaction tests, California Bearing Ratio (CBR) tests (soaked and unsoaked), and consolidation tests. The objectives are to analyze the geotechnical factors causing road subsidence, determine soil parameters at the study site, and provide technical recommendations for road structure repair or improvement. The study is limited to the specified location and focuses on soil properties testing for clay soils, including sieve analysis, specific gravity, Atterberg limits, compaction, CBR, and subgrade testing. The expected benefits include contributing to the scientific literature on geotechnical aspects of road subsidence due to soft soil conditions and providing a technical reference for local government and related agencies in addressing similar issues in the future.