A 90-year-old woman is still in intensive care following a collision on the B1190 near Bardney.
The crash happened about a mile from Bardney just after 5pm on November 9.
It involved a head on collision between two cars, one of which was overtaking a tractor driven by a 51-year-old Potterhanworth man.
A green VW Beetle driven by a 48-year-old Bardney woman collided with a red Volvo driven by a 84-year-old Heighington man.
The 90-year-old passenger in the VW Beetle was taken to Lincoln County Hospital where she remains in intensive care.
Two others were also taken to hospital with other less serious injuries.
The road remained closed until 11.30pm.
Anyone with any information about the crash or those involved is asked to call the Collision Witness Hotline on 01522 558855.