Sadly, her daughter had finally turned her life around when she drove her Mazda Demio out of St Andrew's Rd, through the intersection with Mt Albert Rd and into the wall.
Police are still investigating but have confirmed what Wilson-Davis told the Herald on Sunday, that a shoe was found wedged under the brake pedal. It was not known whether the shoe was there before or during the crash.
Witnesses estimated the car was speeding at 140km/h, but Wilson-Davis had been told it was more likely she was going about 90-100km/h. "She knew that road, she had been at a party with her boyfriend, she was not drunk, and hadn't taken any drugs," said Wilson-Davis.
Tau was not someone who would take her own life, her mother said.
"We are not sure why it happened, except for the fact that this is the best time in Petrina's life.
"She had a job that she loved, a company car, she was in love with her partner, and had two daughters and a granddaughter who she adored. None of us can work this out."
Tau was known within her family as their "colourful tornado" who "lit up" the room with her presence.
But her mother said the system allowed her to "linger" for too long and become state-dependent.
"She got into a rut, wouldn't take advice from whanau even though we all tried to encourage her," she said.
"Her life finally changed when she had her granddaughter, who has just turned1."
The week before she died she had told Wilson-Davis: "Mum, I love my job because I'm around such positive people."
"If she had just been assisted and supported earlier to get off that benefit, this could have been a totally different story," Wilson-Davis said.