The mother of Libby McKay hopes police will fully reinvestigate the death of her daughter now they have reopened their inquiries.
An inquest heard Ms McKay, 27, was driving home from a party with her boyfriend Mike Brown in Christchurch in June 2013 when she fell out of the ute, sustaining serious head injuries.
The couple had attended a party in West Melton, where Ms McKay drank whisky and vodka and smoked cannabis. After she fell out of the vehicle, Mr Brown picked her up off the road, drove to their home in Hornby and then called an ambulance. She died five days later in Christchurch Hospital.
Police are now reopening the investigation after Ms McKay's mother Pauline Webby raised questions about how her daughter died.
Ms Webby told Morning Report she had doubts from the first time she first saw her injured daughter.
"When I walked into the hospital the morning that I got the call that she was in hospital, I went down and I walked into ICU and I was expecting to see Libby with a lot of abrasions and grazes - and she didn't have any of that injury pattern."
Ms Webby said after the inquest she kept asking herself what new evidence she could find to put in front of the coroner to have the case reopened.
"The only question that I could come up with was that her injury pattern didn't fit the form of the accident and how could I prove that."
She contracted an Australian company, Accident Analysis, to look at the evidence, and said the report given to her in March this year backed her conclusions.
Ms Webby said there were "great big gaps" in the work police had undertaken.
She wants a complete reinvestigation of Libby's death rather than just a review of existing files.
"My hope is that the police take this very seriously, fully reinvestigate it, look at all the inconsistencies in the file, look at the report.
"I would also expect that they would have already spoken to the authors of the report from Accident Analysis to talk through what the findings of that report were ... so they fully understand what the contents mean."
Ms Webby said support from National MP Nick Smith had been very significant.
"His support to get the police commissioner to listen to us has, I think, been very valuable.
"We have now got the attention of both the coroner and the police."