The ACT Policing sergeant, known as Dickie, has seen more twisted, deformed and crushed vehicles than anyone could ever want to.

Among the half a dozen grim wrecks at the Crash Team's Belconnen depot last week, Sergeant Dauth pointed to a black Subaru.

Front passenger seat nowhere to be seen, the car was less than half its created width after a crash which killed its driver in March last year.

"The roads were wet, he lost control at an intersection, slid into a tree," he said.

Drugs, alcohol and speed were involved.

A stroller still sat in the open boot. The man - who had a birthday a week earlier - is survived by a partner and baby who weren't in the car.

There have been 44 people die on ACT roads since 2011, with 10 so far this year. The cars or motorbikes involved will arrive at the depot soon after the accident for mechanical examination.

Sergeant Dauth, 60, who spent more than a decade as a mechanic before joining the police 29 years ago, said most vehicles were returned to owner or insurer within a month or two.

"In specific but rare cases, where mechanical condition may be challenged, we will keep them to the conclusion of the court case," he said.

"Brakes, steering and accelerator operation are the items of most interest, but nothing is excluded."

The oldest crash which has left a vehicle now on site was in January 2014, with a trial due to begin next year. In contrast, the Subaru was signed over to police as a road safety caution.

You might imagine the secure compound was the last place a grieving family member would want to visit, but each year a couple do to collect small personal items. A brother of one deceased who had worked on the rebuilt car in the accident visited earlier this year.

"He was able to see the car and fill in missing pieces," Dickie said.

"At times, seeing the crash vehicle seems to help some people grieve or gives them a degree of closure."

While he now personally inspects a minority of the cars, as the oldest member of the crash team it falls to the sergeant (one of two in the team) to inform about four or five families each year - most recently in September - they have lost a loved one.

"You're always going to be mindful of the tragic impact that it's going to have on people - they will remember that day, and they will remember your face forever," he said.

As 10 families prepare for their first Christmas without a victim, Dickie said alcohol, speeding and drugs - in that order - were behind most of the fatalities he had seen.

"I'd say the vast majority could have been easily avoided," he said.

He warned against complacency by people who considered themselves good drivers.

"One of the hard things about working in the crash team is quite often we have to prosecute otherwise nice people for serious offences, because they've done something silly," he said.

"Here we sometimes prosecute Mr "Joe public servant", Mr "never had a parking ticket".

"One night they've made a serious mistake, they haven't had enough sleep, or had a drink too many, and it doesn't have to be high level to have a significant impact on their driving."