A 22-year-old man with a "bright future ahead" has faced court after allegedly crashing a car, with five of his friends inside, into the back of a house in the Perth suburb of Rivervale, killing three and injuring two others.

Zack Thomas Heylen appeared in court on Sunday morning via audio link from hospital, facing three charges of manslaughter and two counts of dangerous driving causing grievous bodily harm.

The court heard Mr Heylen was driving a white utility, meant for five but filled with six, at an alleged speed of 114 kilometres per hour, when it veered off Orrong Road, which has a speed limit of 70 kilometres per hour, just after 5am on Saturday morning.

The ute hit a tree, causing it to spin around and smash into the rear of a brick home, which was empty at the time.

Two 22-year-olds and a 34-year-old sitting in the back of the ute died at the scene.

The 19-year-old passenger in the front and a 23-year-old in the back received head injuries and remain in a serious condition in hospital.

The police prosecutor said Mr Heylen had been out with his friends drinking at two licensed premises before driving towards Bassendean, which is when the crash happened.

The court heard he blew a preliminary alcohol reading of 0.095, with blood taken and sent off for testing and those results expected in 12 weeks.

Mr Heylen was the only person in the car wearing a seatbelt.

While police initially said he was uninjured, it was revealed in court he has three spinal fractures and required surgery.

Magistrate Michelle Pontifex read out the charges over the phone to Mr Heylen, who responded with a 'yes' when asked if he understood them.

Mr Heylen's mother and father were in the back of the court, visibly distressed, his mother struggling to stop herself from crying.

As Mr Heylen remained on the other end of the phone — the sound of a persistent beeping from a hospital monitor could be heard.

Defence lawyer Laura Willox told the court what happened had "forever changed the lives and trajectory of many people".

"None of that is lost on Mr Heylen," she told the court, adding those in the car with him were his friends.

Accused was dux of school

She told the court Mr Heylen lives with his parents and three siblings at their family home in Roleystone.

He was dux of his graduating class, talented at sports and had been accepted to study physics, with his goal to become an astrophysicist.

She said while he had started that degree, more recently he had been working full-time with his father.

In an attempt to obtain bail for her client — which the police did not oppose — Mr Willox said she believed Mr Heylen required both physical and mental health support that could not be met in custody.

"[His] mother is a GP and she had expressed inordinate concerns over his mental health," she told the court.

She said it was, in her experience, extraordinary and exceptional that an investigating officer would not oppose bail for someone facing such serious charges.

The fact the officer did not oppose bail was testament to the type of young man he was, she said.

However, Magistrate Pontifex said considering the seriousness of the charges, with manslaughter carrying a possible term of life imprisonment, that bail was not appropriate.

He was remanded in custody and is next due to face court on December 13.

Tragic few days

Several people gathered at the crash site on Sunday, where flowers had been placed by a tree. 

Among those was Sam Lloyd, who taught some of the men, including one who died in the crash, when they were students at an Armadale high school.

Mr Lloyd said while he never taught Mr Heylen he knew of him and said he and others in the crash had been a tight-knit group of friends while at the school.

"Just shock and sadness," he said of how he was feeling.

"I've been teaching 10 years and it's happened too often, it's too many young people.

"Just slow down, just appreciate everything you've got, all the time you've got, make the most of every day, look after your mates, love your family and just be careful on the road."

Commander Mike Bell of WA Road Policing Command addressed the media again on Sunday, highlighting further fatalities on WA's roads overnight.

At 5pm on Saturday, on Indian Ocean Drive in Guilderton, two women, aged 23 and 31, died after a head-on collision. 

"And then about 11 o'clock last night a 25-year-old male who was out celebrating his birthday, [was] driving on the Goomalling Road (Goomalling-Toodyay Road in Wongamine), left the road, struck a tree and he's in a serious condition," Commander Bell said.

"We suspect alcohol and speed will play a factor in that one but it is still under investigation and in early stages."

The recent deaths have taken the state's road toll to 146, well above the preceding five-year average of 129 deaths for this time of the year.

In another tragedy, a 14-year-old boy died after an off-road motorbike accident in South West WA last week.

The teenager lost control of the bike on Perup Road in Manjimup and crashed about 6:15pm on Tuesday night.

He was airlifted in a critical condition to Perth Children's Hospital, where he later died as a result of his injuries.

Commander Bell again expressed his plea for parents to talk to their children about road safety.

"People need to listen to this message because it can happen to you," he said.

"[We] particularly want to point out young drivers and inexperienced drivers and the need for parents to have that conversation [with] children.

"Just remind them how important they are to the family and how much of a loss it would be without them and how they need to abide by the road rules."