A 37-year-old man from Grimsby is being treated for a serious head injury after a collision on the A46 in Lincoln on Sunday, September 15.
The Air Ambulance airlifted the man to Queens Medical Centre in Nottingham after his Honda motorbike collided with a black Honda Civic near Whisby Nature Park.
Emergency services were called to the incident at around 2.20pm, and the road between the Teal Park and Pennells roundabouts closed for the ambucopter to land.
The road remained closed while the vehicles were recovered and Lincolnshire Police carried out investigations. It fully reopened shortly before 6pm.
Any drivers who witnessed the collision are asked to call Lincolnshire Police on the 101 non-emergency number regarding incident 239 of September 15.