A man from Daventry is in a serious but stable condition in hospital after a crash on the A45 on Sunday December 6.
At about 11pm, a blue Seat Ibiza was being driven towards Weedon when, for reasons yet unknown, it left the road and came to rest in a ditch.
The driver, a 19-year-old man from Daventry, was taken to University Hospital Coventry, where he is reported to be in a serious but stable condition.
The passenger, an 18-year-old man, also from Daventry, was taken to Northampton General Hospital but was later discharged.
Police are appealing for witnesses and anyone with information is asked to call the Northamptonshire Police Drivewatch hotline on 0800 174615.