Geelong Highway Patrol are appealing for witnesses following a collision in Bell Post Hill yesterday morning.
Police believe a white Toyota Hilux and a white Kia Rio collided on Ballarat Road near the city bound on ramp for the Geelong Ring Road about 11.36am.
The Kia was pushed into an armguard railing and the occupants were trapped for some time before being cut free by emergency services.
The driver of the Kia, a 20-year-old Lara woman, was transported to hospital with non-life threatening injuries.
The front passenger, an 18-year-old Lara man, was airlifted to hospital with serious injuries.
The back passenger, a young baby, was uninjured and transported to hospital for observation.
The sole occupant of the Toyota, a 29-year-old Bannockburn man, was transported to hospital with non-life threatening injuries.
He is assisting police with enquiries.
Anyone who witnessed the incident, with information or dash cam footage is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au
