A driver who was texting her boyfriend when she caused a high-speed freeway crash in Perth, which claimed the life of her friend, has been sentenced to three years and eight months behind bars.

Key points: Aine McGrath's friend died after her car veered across traffic and was T-boned

Aine McGrath's friend died after her car veered across traffic and was T-boned McGrath will have to serve 22 months in prison before she can be released

McGrath will have to serve 22 months in prison before she can be released The judge said she showed a selfish disregard for the safety of others

Aine McGrath, 25, was found guilty earlier this year of dangerous driving occasioning the death of 25-year-old Sarah Kelly.

McGrath was using her phone when she lost control of her car on the Mitchell Freeway near Leederville in August 2016, veering across four northbound lanes of traffic before being T-boned by a ute.

Ms Kelly died at the scene.

The car veered across four northbound lanes of traffic before being T-boned by a ute. ( Supplied: District Court )

In the 10 minutes before the crash, McGrath had been having a text conversation with her boyfriend about going to a hotel to have a drink with friends, in which at least six messages were exchanged.

While McGrath admitted texting, she denied she was distracted by the messages, claiming she received the last text "a significant time before" she lost control of her car.

Aine Marie McGrath and fatal crash victim Sarah Kelly. ( ABC News/Supplied )

She maintained the crash was caused when another vehicle — a slower-moving Jeep — came in front of her when they changed lanes at the same time.

Driver prioritised an 'entirely unnecessary' conversation

McGrath, and members of her family in the public gallery, burst into tears when the sentence was handed down.

Aine McGrath sent and received these messages before her car veered across four lanes of the Mitchell Freeway. ( ABC News graphic )

Judge Stephen Scott rejected McGrath's version of events and said the reason she lost control of her car was because she was "distracted for some time reading text messages and sending responses".

He said the text conversation was "over a sustained period of time" while McGrath was driving in traffic at speeds of between 80 and 100 kilometres per hour.

"You engaged in calls and texts that were inconsequential and entirely unnecessary," he said.

"You showed a selfish disregard for the safety of not only your passenger, but other road users."

Judge Scott accepted that McGrath was, and would continue to be, devastated by her friend's death.

But he said she had failed to accept that she was legally responsible for the crash and had instead tried to blame another driver.

He said the main consideration in the sentencing was general deterrence, because drivers continued to ignore the dangers of using their mobile phones behind the wheel.

"Texting, using a mobile phone is obviously dangerous … because it involves so much more than momentary inattention … and there is a likelihood of catastrophic consequences."

Judge Scott said people were becoming increasingly reliant on mobile phones, but the consistent warnings by police and media campaigns about the dangers of using them whilst driving continued to be ignored.

McGrath will have to serve 22 months in prison before she can be released.

Her driver's licence was also disqualified for three years.

Community 'needs to wake up to dangers'

Police commissioner Chris Dawson said community attitudes needed to change.

"We have to continually educate the community," he said.

"It took a number of years before drink driving became, really, an anti-cultural thing for Australians to do.

McGrath (right) was found guilty earlier this year of dangerous driving occasioning death. ( ABC News: David Weber )

"I certainly know when I was a young officer that the incidence of drink driving was not seen in the community as the scourge that in fact it's deserved to be.

"I don't think that the level of community attitude towards the use of mobile phones and texting while driving has actually yet penetrated the public consciousness.

"So we need to continually repeat that.

"Yes people will get fined — we don't obviously want to see the tragic outcomes that have just been referred to.

"I don't think we've arrived at that point, we are going to have to continually hammer that message.