Matt Ruddell, whose former partner Tracey O'Brien died a fortnight ago in a crash that also hospitalised his two children, says people need to learn to "divorce" their phones.
The 27-year-old, pictured, who has spent the past two weeks in Starship children's hospital with his kids, said the loss of his children's mum had been a "wake-up call" for him to get off his phone in the car.
He hoped others wouldn't need to suffer a similar loss to understand the importance of ditching the cellphone.
"Is the call or the one text message really worth it? Is it worth what we're going through?
"It's just been a massive wake-up call ... Just divorce your phone. If there's a call and it's that important, pull over," he said.