<p>Roads are vital infrastructures that enable mobility, support trade, and foster socio-economic development. The performance and longevity of road pavements are predominantly influenced by the properties of the underlying sub-base layer, which plays a crucial role in load distribution and resilience against environmental stresses such as frost heave. This study investigates the evaluation of sub-base materials through two key testing methods, namely the California Bearing Ratio (CBR) and Triaxial Compression tests. These standardized tests assess important material properties, including shear strength, load-bearing capacity, and overall stability, which are critical for optimizing pavement design, minimizing deterioration, and reducing maintenance costs. A mixed-method research design was employed, combining laboratory testing and a comprehensive review of 62 peer-reviewed studies published from 2015 onwards. The findings indicate that sub-base materials with higher shear strength, evaluated through Triaxial Compression tests, exhibit greater resistance to deformation and improved road stability. Materials that meet high CBR standards and possess optimal shear strength values are associated with longer service life, contributing to more sustainable road infrastructure. However, many studies tend to overlook the long-term behavior of sub-base materials under real-world conditions, particularly with regard to moisture fluctuations and traffic loading. While Gaussian Process Regression (GPR) has emerged as a promising tool for predicting material performance, its integration with Triaxial Compression tests remains underexplored. The integration of both CBR and Triaxial Compression tests offers a more comprehensive understanding of sub-base material behavior, informing better design practices and ensuring the selection of materials that contribute to road durability. Moreover, the study emphasizes the importance of field validation to bridge the gap between laboratory findings and real-world conditions. The lack of such validation in current research limits the applicability of laboratory results. Therefore, this research advocates for standardized testing methodologies that integrate both CBR and Triaxial Compression tests, as well as the incorporation of long-term performance evaluations and field validation, to improve the accuracy of sub-base material assessments. By refining testing practices and promoting optimal material selection, this study provides valuable insights for the design and construction of durable, resilient, and cost-effective road infrastructure that can withstand diverse environmental and traffic stresses.</p>