Twenty people died on Australia's roads this Easter, nine more than last year.
The carnage was the worst in Victoria and South Australia, with five people dying in each state.
Two men died and another is fighting for his life after their car rolled on the Hume Freeway while returning home from Canberra to Melbourne on Monday night.
Detective Sergeant Rohan Courtis says the six male friends, aged between 20 and 30, were heading home after competing in a chess tournament.
"Around Easter, it's supposed to be a happy time to spend time with family and friends and it's ended in this tragedy," he said.
Two of the passengers were taken to Melbourne, one to The Alfred hospital with head and chest injuries and one to Royal Melbourne Hospital with a serious back injury.
The driver and another passenger were taken to local hospitals for treatment.
In South Australia, also on Monday night, a male pedestrian died when he was struck at Waterloo Corner, north of Adelaide.
Police say the man died at the scene after being hit by a vehicle on Port Wakefield Road, about 500m north of the St Kilda Road turn-off.
In other states, two people died on NSW roads over the Easter break, four in Queensland and two people in both Tasmania and Western Australia.
There were no Easter road deaths in the ACT or the Northern Territory.