A 24-year-old woman from the Harrogate area suffered a head injury after the car she was driving collided with a tree.
The woman was driving a silver Ford Ka on the A61 between Harrogate and Ripon when the collision took place at 9.40pm on Saturday, August 17.
She was taken to Harrogate District Hospital following the single vehicle collision.
North Yorkshire Police are hoping to trace a black, medium-sized car which was also travelling towards Ripon when the collision occured.
Police say the occupants may have vital information which could help the investigation.
Anyone with any information is asked to contact Traffic Constable Stuart Holden by calling 101 or by email at email@example.com