In an inquest into her death in 2012, senior sergeant Fane Troy said when he arrived at the scene, he found Jessep's cellphone in the driver's footwell of her car with a half written text on the screen.
Troy revealed that Jessep sent 19 texts within a 45-minute period leading up to the crash.
Now, five years after the accident, Jessep's son hopes his story will help people realise the risks of using a cellphone while driving.
"Just don't do it. Problem solved.
"Making a mistake in a car has much bigger consequences than making a mistake doing something else.
Eliot was just 16 when the accident happened in 2011.
"I'm still devastated and I get sad, but I've come to terms with it more."
He said he went from being an only child living at home with his mum, a single parent, to living with family friends.
"I had to grow up really quickly. I lived with some great family friends, but they weren't mum."
Mobile phones have been a contributing factor to 20 deaths on New Zealand roads since 2011.
Provisional data released by police revealed a rise in the use of mobile phones while driving, with the number of infringements surpassing the number of drink driving offences in the last three years.
Between January and September 2016, almost 22,000 drivers were pinged for using a mobile phone while driving, amounting to $1.7 million in fines.
In comparison, 18,600 drivers were caught drink driving in the same period.
The highest recorded number of mobile phone offences in the last eight years, were in 2015 with 28,000 people caught texting, talking or checking their phones behind the wheel.
"In the country, I'm probably one of the people who hate [texting and driving] the most. You don't know what is coming around the corner, there's no guarantee someone else won't cross the centre line and if you're distracted you won't see it," said Eliot.
"The consequences could be huge."
Eliot is the director of an e-commerce company in Hamilton and said he would have loved his mum to see his success.
"When people say 'your mum would be so proud' it sets me off the most."
The 21-year-old said his mum was "loud", "really funny" and "out there".
"She loved people. She worked for St John up until she died, managing a group of about 400 volunteers."
Inspector Pete McKennie said drivers need to be aware of the very real risk that distractions represent.
"Especially talking, texting and checking emails on mobile phones while driving. Put the phone away.
"Put your passengers and other road users first. Nobody wants to be on the road with a driver who is not paying full attention to the road.
"Other drivers and your passengers deserve your full attention on the road."
McKennie said that although the current legislation allows people to use hands-free cellphones while driving, police recommend that drivers minimise the potential for distraction by switching phones off while driving, or pulling over to make or receive calls.
