When I see those memorials I can only think that there are public servants somewhere that had to collect the remains and wash the blood off the roadway. If the family is lucky or can afford the expense of mortuary reconstruction there can be an open casket ceremony, and the fantasy is reinforced. Popular culture is awash with "Teen Angel" songs and romantic movies involving returning ghostly eternally teenaged shades come to work magic on us mere mortals. Who wouldn't want to join that cadre of immortal youth. Sadly soon after the firemen have washed the blood and guts off their hands and thrown up at the station, the candles at the memorial burn out, the flowers wilt and the balloons go flat. The victims of the tragedy are mentioned less and less often, and the county road crew picks up the remains of the memorial and that's that.
Those roadside shrines depress the hell out of me.