Australia has some of the largest underground mines in the world. The network of underground access roads is conventionally made of reinforced concrete overlain on in-situ subgrade layers. Maintenance of these roads is costly and due to the roughness and unevenness of the concrete surface, the vibration-related musculoskeletal disorders (MSD) claims in mining are much higher than in any other sector. The current study aims to investigate the performance of a novel flexible geomat made of High-Density Polyethylene (HDPE) as an alternative to the conventional heavy-duty roads. A series of physical testing (tensile tests), mechanical testing (flatwise and edgewise compression), and structural testing (3-point shear and 4-point bending tests) are carried out in a laboratory environment. The tests validated the favorable properties of the HDPE mats for roads with heavy-duty vehicle traffic. Finite element analyses (FEA) were implemented to simulate the physical test results. Using the validated and calibrated FEA, soil-structure interaction models were developed and performances under different traffic loads were calculated. The soil-geomat FEA intearaction study showed that the stresses are within the acceptable limits for roads with heavy-duty vehicle traffic.