A woman suffered serious head injuries after her car was forced off the road at speed in West Sussex.
Sussex Police said the hit-and-run incident involving a Renault Clio and a Mini took place on the A23 at Albourne, near Hurstpierpoint, on Saturday.
The Clio rolled into bushes after it was forced off the northbound carriageway at about 1315 GMT by the driver of the Mini who fled the scene.
Police said the woman was being treated in hospital.
The force urged the driver of the Mini to come forward.