The probation staff member assisted with first aid until St John arrived, she said.
It was not known why the woman jumped from the car.
Former city councillor Murray Guy and his wife Marion found the woman lying across the centre line.
"There was about half a dozen cars there and the woman was lying across the centre line and was being attended to by an anaesthetist from the hospital. She ascertained the woman wasn't critical ... she was fairly significantly grazed they made sure she was comfortable until the ambulance came.
"She mostly had grazing to her limbs. You would think she had come off a motorbike.
"She was conscious and talking, albeit a little incoherent."
A Tauranga Hospital spokesman confirmed the woman was in a stable condition yesterday.