Police are appealing for witnesses and those who have relevant dash cam footage, following a serious collision on the A30 near Colliford Lake, Bodmin, on Tuesday (July 6).
Officers were called around 13:20pm following a collision between a grey Volkswagen and a Land Rover Discovery on the westbound carriageway.
The driver of the car, a man in his 30s from Norfolk, sustained serious injuries, initially described as life-threatening.
A further three adults and one child in the car also sustained injuries and all were taken to Derriford Hospital.
The driver of the Land Rover, a man in his 60s from Scotland, suffered minor injuries.
Medical treatment was administered soon after the incident by members of the public and emergency services.
Witnesses can contact 101@dc.police.uk or telephone 101, quoting log 0468 of 6 July.