Paramedics treated two male passengers for cuts and bruises.
A witness, who declined to be named, said the car "flew like a rocket through the air".
"They must have got about a half metre off the ground at least. It was spectacular," he said.
"One of them got out straightaway and the other two took awhile. They crawled out and were all cut and bleeding."
Mr Megaw said police had spoken to the car's owner, who was not in the vehicle, and making enquiries to find the driver, who left the scene.
The crash came after a 35-year-old Masterton woman with a three-month old baby in the back seat rolled on the Rimutaka Hill Rd yesterday morning. Upper Hutt police senior sergeant Brent Murray said the baby was not injured, but the woman received medical attention at Hutt Hospital for minor cuts. Mr Murray said the incident happened about 3km south of the summit.
In a separate incident, there were two minor car crashes on State Highway 2 in Solway near the pedestrian crossing on Friday afternoon within about five minutes of each other.
Traffic Constable Raewyn Joblin said in both incidents a car ran into the back of another vehicle stopped at the crossing.
One of the drivers, with a sore neck and back, was taken to Wairarapa Hospital as a precautionary measure.
