The couple, who had moved in with Higginson two weeks earlier, were on their way to Papakura when they saw that there had been a crash.
"We saw there had been an accident and we pulled over to help," McVeigh told the Herald.
"The car looked pretty familiar but it was pretty smashed up... I looked in the window and I didn't even recognise Maddy.
"Then my partner had a proper look and saw who it was..."
The couple could see Higginson was dead, so turned their attention to the woman in the other car, who was travelling with a young baby.
After making sure she was ok, McVeigh went back to Higginson's car and sat there with her friend until her body was taken away.
"I stayed there with her, there were emergency services people everywhere and I stayed so that she wasn't surrounded by strangers," she said.
"I couldn't get in the car with her, so I sat beside it. I spoke to her a little bit, at first I was so upset at her, really upset that she'd left me."
Higginson and McVeigh's parents were friends before they were born and the women have been friends their whole lives.
In the past few months they had become much closer, and McVeigh and Cargill moved out to Awhitu to live with Higginson.
"In the last couple of months we got really close; we've always been there for each other, but in the last few months we had some really rough times and we spent a lot of time together - it was the closest we'd ever been."
McVeigh said Higginson had recently met the love of her life and was extremely happy.
"[Deb] was her first girlfriend," McVeigh said.
"She'd finally fallen in love. She'd had relationships over the years but she had finally fallen totally and head-over-heels in love and was finally enjoying life."
Higginson worked on a dairy farm and "absolutely loved" her job, McVeigh said.
"She loved animals, she was so happy," she told the Herald.
McVeigh said Higginson was a generous person and would be greatly missed by her family and friends.
She is survived by her mother Lisa Nichol and her partner Chris, father Joe Griffin, stepfather Scott Nicol and siblings Malcolm and James Nicol, Ana and Blair Nicol and Hayley and Blake Griffin.
McVeigh said Cargill, who had become close friends with Higginson was also feeling the loss of Higginson.
"She was the type of person who would give anything to anyone that she could, even it she needed it herself," McVeigh said.
"She was so kind, caring and humble."
McVeigh said Higginson loved her family heaps and did whatever she could to protect and help them, and always called them to catch up.
"She had a kind heart, she was always cheeky but she was like a big sister to me, she's six months older than I am," McVeigh said.
She said Higginson's partner was "absolutely devastated" by her death.
"A couple of weeks before she died, they made it official - they were finally girlfriend and girlfriend," she said.
"She's not very good, we've been visiting her every day."
McVeigh wanted everyone who knew her mate to know that she cared about them.
"Every single person that was in and around her life, she cared about them so much and she cared about what was going on with them," she said.
"Maddy wouldn't want them to be upset for her, she would want them to find the positives, she'd want to make everything alright for them so that they didn't have to fell the pain that she caused..."
Higginson's funeral will be held at 11am on Thursday at Grahams Funeral Home Chapel in Tuakau.
A police investigation into the crash is ongoing.
