A woman was rushed to hospital with serious injuries after leaving the road and smashing into telegraph pole near Caythorpe village.
The crash happened at around 2.54am on Heath Road, Normanthan, near Grantham.
One vehicle, a blue Ford Fiesta, was involved.
Lincolnshire Police said the driver, a woman, received serious injuries and was taken to Queen’s Medical Centre in Nottingham.
A spokesperson from the force said: “We would like to speak to anyone who saw the blue Fiesta travelling on Heath Lane prior to the collision or anyone who witnessed the car leave the road and collide with a telegraph pole.”
Anyone who witnessed the incident or has any information is being asked to call 101, quoting incident number 25 of March 15.