A man in his 20s is fighting for his life in hospital after a car flipped over on the A31 near Alton on Saturday morning.
Police were called at 11.21am to reports of a single vehicle collision between the Chawton roundabout and A339 Selborne Road junction on the east-bound carriageway involving a black Seat Leon.
The Hampshire and Isle of Wight Air Ambulance landed in a nearby field and officers confirmed a man in his 20s was taken to hospital with life-threatening injuries.
It is understood he was transported by air. A motorcyclist was reportedly first on the scene, and called the emergency services.
Delays of two-plus hours were reported by some motorists caught behind the road closure, with others choosing to drive across the central reservation to escape the traffic jam.
It follows a less serious collision at the same location earlier in the week.
Anyone with information or relevant dash cam footage is asked to call 101 or report online via the police's website, quoting reference 44230441281.