Detective Inspector Marcus Boorman, the officer in charge of local road traffic operations, is a former Victorian who served with Senior Constable Lynette Taylor, one of the four officers killed in a single major crash on Melbourne's Eastern Freeway at Kew on April 22.

As a result of that incident four more names are now up on the wall, their touchstones joining more than 700 already placed there.

The Kew incident, in which a truck ploughed into the police officers as they stopped to question a speeding driver by the side of the freeway, resulted in the worst loss of life in a single incident by Victoria's police force in its 167 years.

The driver of the truck has been charged with four counts of manslaughter. The driver of the speeding sports car, who had been clocked at 149km/h when police pulled him over on the freeway around 5.30pm, is facing a separate raft of charges.

"It's hard to comprehend the disbelief you feel when you hear about losing four colleagues in one single incident like that," Inspector Boorman said.

"It stops you in your tracks, it really does."

Attendee numbers were fewer at the memorial this year because of the COVID-19 pandemic. Usually every jurisdiction sends representatives to the service, but this year that wasn't possible because of border restrictions and quarantine regulations.

But the police "family" which gathered there was all keenly aware of how this year, of all years, has wrought such an incalculable impact through the lost lives of their colleagues and how that loss has deeply affected the four officers' families.

When serving with the Victorian police before moving to Canberra, Detective Inspector Boorman lost a close friend and fellow officer in similar circumstances on the Melbourne Ring Road.

Again, it started as an incident in which a driver was pulled over - as happens numerous times every day for those in road policing - and the policeman was struck and killed instantly by a passing motorist.

"I know quite a few names that are on that wall," Inspector Boorman said.

"In 30 years of policing, I've lost a lot of good mates and colleagues. And I've been to far too many police funerals."

He said that he understood that Tuesday's ceremony wouldn't "mean much to the general public out there but to police, it's a special time to pause and reflect" on the intrinsically risky work they do every day.

"It's a sad reality but it's not something you think about every day because if you stopped and thought about it every day, you wouldn't go to work," he said.

"You do a lot of reflection at times like this. But then you just get up and get on with it."

The Boorman family has two direct and strong connections with road policing. Marcus's brother, Martin, now retired, was an Inspector in charge of the state's alcohol and drug driver detection unit and whose expertise and operational knowledge is widely sought and respected.

The Kew tragedy, too, was a powerful reminder of how dangerous "working the road" is for traffic police everywhere.

"The risks are great in road policing. Every interaction; you don't know who you are going to be talking to, who's in the car as you approach them, and the road safety issues that arise when you're responding," Inspector Marcus Boorman said..

"We train for it, of course, and self-preservation is a big thing, too, you know, but sometimes these tragedies just happen and you wish you could turn back the clock but you never know what can happen, you just never know."

He said that if there was one message he would like to convey to the public was that police were just out there trying to do a job the best way they can.

"All I'd say to people is to spare a thought for those officers and their families who have paid the ultimate price."