The cause of the damage is the lack of proper adhesion between the solar panel (including top layer) and the underlying concrete of the SolaRoad elements. Although the solar panels are unintentionally fixed to the concrete immediately after production, from that moment on a process starts, initially on a small scale and not visible to the eye, in which the solar panel gradually detaches from the concrete. This process occurs under normal outdoor conditions, even without loads from traffic. The speed at which this process occurs varies greatly from place to place. As the detached areas become larger, (small) deformations and movements in the solar panel may start to occur, under the influence of temperature fluctuations. If (heavy) vehicles then drive over them, damage such as that observed in the pilot projects will occur.