Mr Ruddell said he wanted the crash to serve as a reminder to people of the dangers of using your cellphone behind the wheel.
It wasn't just Ms O'Brien who might have been guilty of it, he said; there were too many New Zealanders ignoring the law and the consequences could be deadly.
In 2009, it became illegal to use mobile phones while driving.
Since then, the number of recorded monthly offences had almost doubled, police statistics show.
"I'm bad for it myself," Mr Ruddell admitted.
"But there's certain times and places you don't need to be on your phone and obviously behind the wheel is one of them.
"I plan when I get back [to Tauranga] to start printing T-shirts and posters with 'divorce your phone', or words to that effect."
Mr Ruddell said he wanted to lay a wreath at the site of the crash that killed his former partner of six years.
He also hoped to also put up a billboard urging people not to text while driving.
He said that while the police hadn't confirmed that Ms O'Brien's use of her phone was the sole cause of the crash, they had told him it was likely "a contributing factor".
Even before the police statement on the day of the fatal crash last Saturday - Mr Ruddell had posted his thoughts on Facebook: "May this be a massive wake-up call to everyone never txt and drive."
He said he just knew his assumption wouldn't be far from the truth.
"For anyone that does know her, if she wasn't on Facebook or texting, she was just app after app.
"She had a big group of friends, she was a very social person ...
"Her phone was glued to her hand. She never went anywhere without it."
