A MAN has suffered serious head injuries after the grey Mercedes he was travelling in ploughed into the central reservation on the A1 between Grantham and Long Bennington.
Both the north-bound and south-bound carriageways were initially closed by police to allow the air ambulance to land following the collision at about 3.15pm.
One lane on each carriageway is now open and traffic is slowly moving.
The 32-year-old man is in a serious condition in hospital.
Polie are appealing to anyone who witniessed the collision to call them on 0300 111 0300, quoting incident number 267 or August 16.