Roads are vital for transportation infrastructure in developing nations like India, with most being flexible pavement roads. Evaluating the condition of these pavements is crucial for safety and efficiency. Traditional methods are often time-consuming, disrupt traffic, and involve destructive techniques like core cutting. Non-destructive testing methods, such as Ground Penetrating Radar (GPR), offer a promising alternative, enabling quicker evaluation without compromising structural integrity or traffic flow. This research investigates the use of air-coupled 900 MHz GPR for assessing flexible pavement crust thickness. Conducted on roads in New Delhi, the study assesses the viability and efficacy of GPR. Data collection was done using K2fastwave software in distance mode, followed by post-processing with IGS Geo radar GERD HD software. The GPR system, featuring 900 MHz antennas, was mounted on a survey vehicle with a cantilever support frame. The results from GPR were compared with traditional core cutting methods to validate accuracy. The findings showed a lowest error rate of 6.36% in type-1 surveys, 6.53% in type-3 surveys, and 8.15% in type-2 surveys. This indicates that the GPR system is effective in accurately detecting pavement depth, particularly in type-1 survey and type-3 surveys, highlighting its efficacy as a non-destructive tool for pavement evaluation.