An 18-year-old man has been flown to Southampton in "critical condition" after a road crash.
He was driving a car southbound on Grande Route Des Mielles, known as Five Mile Road, late on Sunday.
Police said the car "left the carriageway" coming to rest at the side of the road.
Three teenage passengers, males aged 17-18, were also taken to hospital for treatment after emergency services arrived at about 23:00 BST.
All four men in the car, a Peugeot 106, were aged between 17-18.
One of the passengers remains in a serious but stable condition at Jersey General Hospital, police said.