Katikati senior constable Lindsay Freeman said the vehicle crossed the centre line.
The car then hit a ditch, catapulted up, rolled through a fence and ended up on a piece of farm land, he said.
Mr Lindsay said he did not normally police the area but knew efforts had been made to widen and straighten sections of Whakamarama Rd.
Whakamarama Rd resident of more than 20 years Rachael Jeffrey said she was at home when she heard the car crash through her fence.
Mrs Jeffrey said she heard the crash from inside her house.
"Just big bangs and dust. I was coming out the back door to see who was coming down and you just saw all the dust.
"We ran straight over, I called my husband, and assisted.
"The driver was out and the passenger was over [slumped over in the front of the car] and they were all panicking so I came in and started talking to them and said: 'You're going to be all right.'"
Mrs Jeffrey said the driver was agitated but okay.
"There have been quite a few accidents here."
Another Whakamarama Rd resident, who did not want to be identified, said he had always been concerned with the traffic along the road.