Police were called out to Manston Lane, near the roundabout with William Parkin Way, at about 8.45pm on Saturday.
A grey Audi Q3 and a grey Nissan Juke, which were travelling in opposite directions, had collided.
The driver of the Nissan, a 22-year-old woman, was seriously injured and remains in hospital - where she is fighting for her life.
The driver of the Audi, a 34-year-old man, and an eight-year-old girl, who was a passenger in the vehicle, both suffered serious injuries that were not considered life threatening.
They are both still in hospital.
Police want to speak to anyone who may have witnessed the crash, particularly those who may have dascham footage.
The Nissan was travelling away from the William Parkin Way roundabout in the direction of Manston and the Audi was heading in the opposite direction.
Anyone who witnessed the collision or the movements of either vehicle in the time leading up to the crash is asked to contact the Major Collision Enquiry Team via 101 quoting Operation Pearlmere reference 13220330463 via 101 or online via the Live Chat