"I don't know if she's done anything wrong at this stage. We don't know what speed she was travelling at."
He said if the car had blown up from a petrol leak they would investigate things such as the petrol tank capacity, where it was last filled up and with how much fuel.
"There's a lot of background issues and things that are plainly obvious, including calculations around speed, force direction etc. There's a huge raft of things."
An adult passenger in the other car, a Mazda people mover, was from Rotorua. Mr Campion said that passenger sustained minor injuries, including seat belt burns.
The crash happened on State Highway 2, east of Poplar Lane.