Aaron was planning to marry his girlfriend. Instead, he gave her a ring at her funeral.

On the morning of November 8, 2016, Aaron Roberts was stuck in a traffic jam when he had an eerie feeling.

He began frantically phoning is girlfriend, 26-year-old Danielle McGrath, who he knew used the road nearby to walk to the train station to get to work. When she didn’t answer, Aaron ran from his car to the front of the traffic jam, where his worst fears were realised.

Aaron saw his girlfriend’s handbag, and its contents, strewn across the street. He realised the woman, lying on the road and covered by a sheet, was Danielle.

The 26-year-old was hit by a truck and killed by a 59-year-old man while crossing the road on a green signal in the south Sydney suburb of Caringbah.

Now, more than a year later Aaron told a Sydney court that before Danielle's death he had purchased an engagement ring and had been planning a surprise proposal before her death.

Instead, he placed the ring on his girlfriend's finger at her funeral, two weeks after her death.

"I lost the brightest part of my day, my best friend and my future wife," an emotional Aaron told the NSW District Court on Thursday.

He said her death had left a massive hole in his heart that he would carry for the rest of his life.

Aaron shared his victim impact statement as part of the sentencing of truck driver David William Edward Grice, who last year pleaded guilty to dangerous driving causing death.

Under questioning from his lawyer, Grice on Thursday said he hadn't seen the red arrow signal when he turned at the intersection but he accepted after watching dashcam footage that it was clearly visible on the screen.

He said he didn't check the pedestrian crossing before turning because he was focused on other vehicles on the road.

Ms McGrath's father, Bill, said he would never forget his wife's screams after Aaron called to tell them their daughter was dead.

"Every day since my wife cries herself to sleep and wakes up the same," he said.

"She sleeps with a piece of Danielle's clothing under her head for comfort."

He said it was incredible to witness Aaron putting a ring on his daughter's finger at her funeral but it was also unbearable to see the young man go through so much pain.

On the day of her death, Danielle's mother, Helen Kerr McGrath, wrote on Facebook she wished she could "change places" with her daughter.

"I loved you the moment you were born, not a day went by that you would make someone smile and laugh," she wrote.

"I don't know how I am ever going to get through this and I will be waiting everyday to have our regular call just to tell me you love me."

Grice, in an apology letter he read to the court, said he couldn't change what had happened and he was "terribly, terribly sorry".

"I am grieved to the depths of my being knowing that I am responsible for taking a precious girl from you," he said.

"My heart is crushed. I'm devastated that my judgment has done so much damage to so many people and lives."

- With AAP.