The woman aged in her seventies was in a Honda HR-V car travelling down Cragg Lane towards Brighouse Road in Denholme near Bradford at around 8am on Wednesday (Nov 21).
The vehicle struck a metal fence at the side of the road and then went down a hill before colliding with a dry stone wall on Brighouse Road.
The woman and a man aged in his seventies in the car were injured and were taken to hospital.
The woman remains in hospital where her condition is described as critical but stable.
The man also remains in hospital where he is receiving further treatment.
The Western Area Roads Policing Unit is investigating the collision and anyone who witnessed it is asked to contact them on 101, quoting log reference 0275 of 21 November.