Bleeding is a phenomenon that usually occurs during periods of intense heat, mainly on roads coated with thin surfaces, such as surface dressings (SD). A surface dressing is a treatment consisting of successive layers of binder and aggregates. Bleeding is when bitumen rises from the thin layer to the surface. This phenomenon is exacerbated by hot summer weather and by the level of traffic constraints. When bitumen becomes viscous or even liquid, it is no longer able to ensure maintenance of the surface layer and the gravel that composes it. When bitumen rises to the surface, it creates smooth and slippery areas on the traffic lanes on the road. In cases of extreme heat, the bitumen wraps around the tyres of vehicles, leading to ravelling (also referred to as streaking or peeling), which can result in the disappearance of the thin layer at various points of the traffic lanes.