A White Lady is a type of female ghost purported to appear in many rural areas, and who is supposed to have died or suffered trauma in life. White Lady legends are found around the world. Common to many of them is the theme of losing or being betrayed by a husband or fiancé. They are often associated with an individual family line, as a harbinger of death. When one of these ghosts is seen it indicates that someone in the family is going to die, similar to a banshee.
Generally, the aspects of this phenomena are that the ghost is female, dressed in late era Victorian garb, seen along a rural road, and associated with some local legend of tragedy.
This is a re-enactment of a bizarre car accident caused by a spirit in Sintra Portugal: