Bus seats experience random dynamic loads due to road conditions and suspension systems, affecting force transmission, structural damping, and input vibrations. Given their welded structure, a numerical validation procedure has been developed to assess durability using field-measured signals from specialized test tracks, where vehicles undergo structural testing, validation, and certification. This study focuses on numerical fatigue life assessment through time- and frequency-domain simulations, validated via numerical-experimental correlation. Processed field signals are applied to numerical models and, when necessary, drive physical test benches for accelerated durability testing. A key aspect is the use of accelerometers on seats to capture acceleration data for analysis. By integrating real-world field data with advanced simulations, this study establishes an efficient methodology to validate seat structural integrity and endurance under operational conditions.