Chief commissioner Graham Ashton had hoped detectives would be able to speak to Singh Bajwa yesterday.
It comes as detectives were last night investigating whether methamphetamine played a part in the crash.
Police sources told the Herald Sun a meth pipe was found in the truck's cabin moments after the crash in Kew on Wednesday.
Singh Bajwa was allegedly overheard saying "I was looking down in the cabin and I looked up and they were just there" before he blacked out after the crash.
Analysis will continue on how the truck swerved across lanes before hitting two police cars and mowing down the officers dealing with allegedly drug-affected Porsche driver Richard Pusey.
Investigators from the homicide squad and major collision investigation unit have been involved in the probe. Truck driver Singh Bajwa, whose blood sample was taken after the crash, remains in hospital.
Police said the father-of-two was still unfit to be interviewed yesterday morning but were hopeful of being able to talk to him last night.
"The driver of the truck has been admitted to hospital. He is expected to remain in hospital for a number of days and is unfit to be interviewed at this time,'' a Victoria Police spokesman said.
The blood sample taken from Singh Bajwa has been analysed and police have been given the results, Ashton confirmed.
"The driver of the truck is in medical care at the hospital,'' Ashton said.
"There's an opportunity to have him reassessed as we speak by our medical forensic officers.''
There was no answer at the truck driver's home on Friday.
One Cranbourne resident, who has lived beside Singh Bajwa for more than 12 years, said he was shocked to learn his neighbour had been involved in Wednesday's crash.
He said Singh Bajwa was a "great guy" who had been driving trucks for many years. He said the truckie previously ran a business transporting new cars.
"I'm just shocked and sad that he's in this situation. The family have been here almost as long as we have and we love them — they're great people," the neighbour said.
"He's been driving trucks for years and he seemed to be healthy. I don't know what happened.
"We haven't heard from his family since it all happened. I hope they're okay — we'd help in any way we can."
Another resident described Singh Bajwa as "an awesome neighbour".
"It's been a shock for everyone. We can't believe it," she said. "I don't know what happened but I think it must have had something to do with his health."
One of Singh Bajwa's childhood friends from Griffith, NSW, said the truckie was never in any trouble growing up.
"As a young bloke he was into cars. He was a gentle soul who would not harm anybody," he said. "He had moved away to Melbourne in the '90s so I have personally not seen him or know what he has been up to.
"It's a shock all right."
