She was removed from the car by St John Ambulance staff and transported to Hawke's Bay Hospital.
Last night, a HBDHB said the woman - aged in her 70s - remained in a stable condition.
Police said alcohol was not thought to be a factor in the crash. They believed she must have been wearing her seat belt, otherwise her injuries would have been more severe.
Mr Ormerod said it was very lucky there was not any oncoming traffic when the driver lost control.
Although fire services were called yesterday, they were not required to free the woman from the car.
Police inquiries into the crash would be ongoing. The serious crash unit would not be investigating.