As the automotive industry experiences faster growth, it has become imperative to address the escalating solid waste, particularly non-biodegradable tire and rubber. This paper explores the potential of crumb rubber pyro oil (CRPO) as a modifier for base bitumen VG30 in flexible pavements. Examining different concentrations of CRPO, the research assesses their impact on the physical characteristics of modified bitumen, including viscosity, penetration, softening point, and ductility. Mechanical strength is further examined through the Marshall stability test. Beyond the study of physical attributes, the study delves into CRPO’s role in reducing permeability in the surface layer and its resultant influence on binding strength. This inquiry addresses challenges in bituminous mixes, often assumed impermeable. Pavement distresses, such as stripping and pothole formation, have been correlated with water presence in the bituminous layer. The study evaluates bituminous mixtures using falling head permeability testing techniques. The study intends to strategically decrease water intrusion into bituminous mixes by examining how CRPO modification affects permeability in the surface layer. This decrease in permeability can become an important component of the overall goal of reducing pavement distresses and guaranteeing the longevity of flexible pavements in the face of changing difficulties in the automobile sector.