Pre-emptively, she hit the brakes.
"When they came down the corner and on the wrong side ... [I believe] if I had been going 100km/h still, we would have [gone] straight into them."
Ostern said she was glad there was no traffic behind her at the time.
"Had a car or a truck even been behind me, it could've ended extremely differently ... especially a truck, it would have just taken us out."
She was glad she was "really paying attention" but said she was a little nervous to drive again.
"We do drive that road every day and so obviously you get used to driving it and get a little bit complacent yourself.
"I need to pay attention at every single turn and focus and not get complacent and it was definitely a reminder."
It was also Ostern's 25th birthday on Monday when the incident happened.
"Happy birthday to me," she said with a laugh. "A near miss."
Vermeulen said Ostern "slamming on the brakes" woke him up.
"I woke up being greeted to a van like pretty much directly in front of me.
"It's like a holy s*** moment."
Vermeulen said they pulled over to collect themselves but the van was "long gone".
"If it wasn't for my partner slamming on the brakes and going off to the left a little bit, it would've been a crash. I have no doubt about it."
He believed the van was "completely over the centre line".
"The video doesn't do it justice either as to how close they actually were."
Vermeulen said he was planning to report the incident to police last night.