EPS Geofoam is an appropriate material for reducing dead loads of road embankments and hence, mitigating settlements of pavements constructed over poor ground conditions. It has been used successfully in many projects since its appearance in 1960’s, yet, there are still pitfalls regarding its appli-cation and design, requiring deeper investigations. A serious problem is related to insufficient functionali-ty of such backfills in preventing ruts on the pavement surface. In this paper, results of a series of cyclic plate load tests are presented, describing the influence of soil thickness, as an influential factor, on the performance of these embankments. Nevertheless, this thickness is not an independent factor. It is also dependent on the density of EPS in the subsequent layers. In practical applications, two layers of EPS with different densities are used and the density of the bottom layer should be minimized in order to re-duce overall cost of the pavement along the highway. It has been observed that improper thickness for soil layer (less than 40 cm) above subsequent EPS layers of 30 and 20 kg/m3 (top and bottom layers re-spectively), significantly reduces the ability of such pavements to tolerate against rutting when a noticea-ble number of cycles of loading is applied.