<p>Whole-body vibration (WBV) exposure remains a critical occupational hazard for heavy vehicle drivers, with prolonged exposure linked to musculoskeletal disorders (MSDs). This study presents a comprehensive field-based evaluation of WBV exposure across diverse heavy vehicle categories, highlighting the real-world performance of seat suspension systems. WBV measurements were conducted on 17 vehicles—encompassing both on-road and off-road types—using tri-axial and uniaxial accelerometers strategically placed at the driver–seat interface and the vehicle floor. Exposure metrics, including Daily exposure values A(8) and Vibration Dose Values VDV(8), were computed in accordance with ISO 2631-1 (1997). Seat transmissibility was quantified via Seat Effective Amplitude Transmissibility (SEAT) using both RMS and VDV-based methods. Statistical comparisons across vehicle groups were performed using the Kruskal-Wallis test and post-hoc Dunn’s test. Results showed that on-road vehicles with conventional seats exhibited the highest WBV exposure, with A(8) values often exceeding recommended limits. Off-road vehicles with conventional seats had moderate exposure, while suspension seats significantly reduced WBV levels, although some showed amplification due to improper tuning. SEAT analysis indicated that several conventional seats amplified vibrations, while most suspension seats attenuated them. Significant differences in A(8) and VDV(8) values across groups were observed in the X and Z directions (<i>p</i> &lt; 0.05), with no significant difference in the Y direction. Overall, suspension seats reduced WBV exposure but varied in effectiveness, highlighting the importance of proper seat design and tuning for optimal vibration attenuation.</p>