Bird baths: Bird baths are localised pavement surface areas with slighty lower elevation than surrounding pavements. It is due to subgrade failure.
Raveling: It is the ongoing separation or removal of aggregate particles from the surface.
Pot holes: Small bowl shaped depression in the pavement surface that penetrate all the way through the asphalt layer till the base course.
Subsidence: It is a localised or abrupt lowering of the road surface. It may result from poorly compacted backfill, poor local drainage.