A 30-year-old man has been arrested on suspicion of attempted murder after a vehicle left the road on the A15 Waddingham on Thursday night.
The man, who was a passenger in the car, remains in police custody and will be questioned in due course. The female driver received minor injuries.
It happened at around 11.30pm on Thursday, September 12 and the road was closed for a short period on Friday while the vehicle was recovered.
Lincolnshire Police said: “This incident is not being treated as a road traffic collision. No further details are available at this time.”
Anyone with information that can assist with the investigation should contact police on 101 quoting reference 513 of September 12.