Trista Curry, 31, and her daughter Avalon, four, miraculously survived the crash in March last year but tragically Camden, nine, and baby Maxwell, 19 months lost their lives.
The family were on their way to relatives in Minnesota, US, for Easter when the tragedy happened.
But less than a year after later, Trista gave birth to twin girls Eloise Maxwell and Isla Camden who she named in a touching tribute to the brothers they will sadly never meet.
Trista, from North Dakota, and her children had only been on the road for half an hour on March 25 2018 when their SUV began to slide in bad weather.
The dental nurse says what happened next is a bit of a blur, but she remembers feeling helpless as a bakery delivery vehicle smashed into the right side of her car.
“I looked up and watched in disbelief as the front of the lorry came towards us,” she said.
Remembering the horrific incident Trista said she knew something was bad when she didn’t hear the children crying.
“Nobody was crying, my boys were gone instantly, there was no screaming or crying or anything like that,” she said.
Trista suffered five broken ribs, a lacerated liver and a fractured skull in the crash while her daughter Avalon was treated for a head trauma and brain bleed.
The mum says the loss of her sons didn’t sink in until she left hospital two weeks after the crash and returned home.
“I went back to our apartment without them and saw all of their stuff. It hit me that they were gone.”
She found out she was pregnant with the twins just three months later, and at first the news terrified her.
“It was a lot to take in,” she explains. “I didn’t think I wanted any more kids, I just wanted my boys back.”
But when Trista gave birth to Eloise Maxwell and Isla Camden on February 18 at Sanford Medical Center, the same hospital where she had been treated following the car crash, she ensured that Camden and Maxwell were represented.
“I was bawling when they were born,” she says. “All the hospital staff knew about the boys.
“We had t-shirts made for Avalon saying ‘big sister’ and a t-shirt with the boys on it saying ‘big brothers in heaven’.
“It made me feel like they were there.”
Trista said that when she found out she was having girls she was a little upset as she had hoped to be a boy mum again.
“But I think it’s for the best that they are girls and I knew that Camden and Maxwell were fluid names that would work for girls too.
“I knew immediately that I wanted their names involved.”
Trista paid tribute to her two boys, describing Camden as a fantastic big brother and Maxwell as a baby who could light up a room.
“They would have been over the moon to have two little sisters,” she added.
The mum has now set up charity CamdentotheMax in honour of her boys and is speaking out about her experience to offer support to other parents who find themselves suddenly bereaved.
She said: “I’m not far along enough in my grief to give people advice but I do know as a mother who lost two kids, all I want to do is talk about them and say their names.
“Some people act like it is taboo to mention Camden and Maxwell.
“But I’m big on telling people to say their names, ask about them and let me tell stories about them.
“All you can do when your kids are gone is talk about them.”