Bleeding or flushing is shiny, black surface film of asphalt on the road surface caused by upward movement of asphalt in the pavement surface.
[1][2][3] Common causes of bleeding are too much asphalt in asphalt concrete, hot weather, low space air void content and quality of asphalt.
[4] Bleeding is a safety concern since it results in a very smooth surface, without the texture required to prevent hydroplaning.
Road performance measures such as IRI cannot capture the existence of bleeding as it does not increase the surface roughness.
[2] But other performance measures such as PCI do include bleeding.