Bailey Richard Hogan Jones, 22, has pleaded guilty to culpable driving in relation to the December 2018 crash that led to the death of 21-year-old Nukyah Gunthorpe.

Jones' car collided with a truck on Somerville Street, Flora Hill, a couple of hours after he had smoked the drug ice.

He was also speeding, although how quickly was a matter of contention between prosecution and defence.

His lawyer, Eleanor Millar, told the County Court on Wednesday that Jones suffered PTSD and complex grief at the time of the crash, having lost his newborn son four months earlier and a friend in 2016.

The court heard a psychologist reported this led to lowered inhibitions and a higher likelihood of taking risks, and she concluded Jones was affected by both his mental state and his drug intoxication when the offending occurred.

Ms Millar said the psychologist also reported that Jones' mental health issues reduced his ability to cope in custody, and time in prison was likely to see his mental health deteriorate further.

But Crown prosecutor Robyn Harper said there was no link between Jones' mental health and the crash, given his drug use.

"This offending has all the hallmarks of a drug-affected offender," Ms Harper said.

Ms Millar also submitted Jones had some awareness of what was about to happen in the moments before the crash, as he steered to the right in anticipation the truck was about to turn in front of him, but the truck driver also steered to Jones' right.

But Ms Harper said his drug impairment and speed contributed to his inability to make a decision when faced with the truck ahead.

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The court heard Jones sustained a fractured pelvis, fractured ribs, a partially collapsed lung, a lacerated liver, bruising to his heart, and a laceration on his scalp that went to the bone.

Ms Millar said her client began using cannabis at the age of 13 or 14, and first used ice at 15.

After the death of his friend, she said, Jones' use of ice increased dramatically.

Ms Millar said Jones was abstinent from the drug during Ms Gunthorpe's pregnancy, but he relapsed after his son's death.

The court Jones had a limited but relevant criminal history, which included improper driving of a vehicle, causing it to lose traction, and home invasion.

Ms Millar said Jones was still young and had meaningful prospects of rehabilitation.

He had also expressed genuine remorse, she said, and insight into his behaviour.

Ms Millar submitted Judge Kevin Doyle needed to consider the three-year sentence Jones was already serving for the home invasion.

Jones' licence must be suspended for at least two years.

Ms Harper said this period should begin upon Jones' release, but Ms Millar said his work history suggested he was likely to get employment labouring, for which he would need to drive.

The court heard evidence on Tuesday from two expert witnesses on the alleged speed at which Jones was travelling when the crash occurred.

Judge Kevin Doyle must consider this evidence and decide which is accurate.

Jones has also pleaded guilty to driving an unregistered vehicle and committing an indictable offence on bail.

Sentencing is adjourned to a date yet to be determined.

Note: The Bendigo Advertiser has previously reported Jones' surname as Hogan-Jones, in accordance with court documents. However, defence counsel have since clarified that his surname is Jones.

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